# Garn hydronic design



## Antman (Dec 31, 2015)

I'd like to get feedback on my proposed Garn hydronic design from all the experts out there! I tried to simplify the design by keeping it unpressurized. I plan to heat 2 houses, a 25,000 gal salt pool, and a 500 gal hot tub. My focus at this time is on the larger of the 2 houses. The smaller home can be delayed until next year. We are completing the construction of a carriage house which houses a Garn 2000 and its location was strategically chosen because it is between the 2 houses and on one of the highest locations on the farm which is 3' above the bottom floor of both houses.

While I want to make it simple, I am open to suggestions about how to make it better even if I have to scrap the entire design. Fortunately, I have my wife's support and I'd like to keep it that way by getting it right on the first attempt . I was hoping to draw from all the wisdom from those who post on this site so I can hopefully provide insight for others who might make the plunge and become more self-sufficient.

I guess the biggest unknown for me at this time is whether a solenoid would be sufficient to keep water elevated at the highest point in the system which happens to be where a 17x20 and 20x20 supply plenum need water coils for the updraft propane furnaces. The bottom floor has 10' ceilings and the second floor has 9' ceilings. All 3 DHW tanks and a 14x20 propane furnace are in the attic at the level of the 2nd floor which is the level where any pumps and manifolds would be installed. However, the 17x20 and 20x20 propane furnaces are above the ceiling of the 2nd floor which is 16' above the level of the Garn's slab.

So, this means that there is an additional 5' to raise water to those 2 supply plenums. This puts me 5' above the maximum 16' rise mentioned in the Garn design manual. I was hoping that zoning with circulators might offset this additional 5'. Could this work or should I just incorporate a FPHX and pressurize?


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## TCaldwell (Dec 31, 2015)

Is the pool heated all year?


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## jebatty (Dec 31, 2015)

Some red flags pop up for me. The relate to the pump head in your system resulting from the 300' of 1" pex underground (is that one way or round trip?), the 230' of 1-1/4" pex underground (is that one way or round trip?), the 1-1/2" pipe main lines to/from the Garn, plus the distribution plumbing for each heat emitter, plus all the fittings, etc.

For a partial explanation of my concern I will start with P1 0013 circulator. The "sweet spot" for the 0013 as shown by its pump curve is at 18-20 gpm which occurs at a pump head of 16-18 feet (about 5.6-7.8 psi). A flow rate of 18-20 gpm at a delta-T=20 would move 180,000-200,000 btus. But my pex pressure drop table shows that at 18 gpm the pressure drop is 0.069 psi/foot, or 15.87 psi at 230', or pump head of 36.5 feet. It is clear that the 0013 will not be able to flow 18 gpm or supply btus in the range of 180,000-200,000. Actual results will be even worse because fittings, valves, etc. add additional pressure drop and pump head.

To get closer to what actually may happen based on your design, and if I don't consider pressure drop from fittings, etc., and I assume a flow rate of 14 gpm, then my pex pressure drop table shows that at 14 gpm the pressure drop is 0.044 psi/ft, or 10.12 psi at 230', or about 23 feet of pump head. The pump chart for the 0013 shows that it will move somewhat less than 14 gpm at 23 feet of pump head, which will move 140,000 btus at delta-T of 20.

Obviously, if the 230' is only one-way, the problem is much worse.

Unless about 140,000 btus is all you need at this location, based on what I see from your design chart, your underground pex may be seriously under-sized for the distances involved and there may be other design issues as well. A similar analysis can be made concerning your 300' pex run, and I would be very surprised if serious issues do not exist with that design as well.

The Garn WHS200 is a beast of a boiler, rated at 325,000 btus maximum. For it to perform according to its capacity, you need an appropriately designed system.


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## Antman (Jan 1, 2016)

TCaldwell said:


> Is the pool heated all year?


I haven't heated it in the past, but I plan to keep it at 85-90F with the use of a solar blanket.


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## Antman (Jan 1, 2016)

jebatty said:


> Some red flags pop up for me. The relate to the pump head in your system resulting from the 300' of 1" pex underground (is that one way or round trip?), the 230' of 1-1/4" pex underground (is that one way or round trip?), the 1-1/2" pipe main lines to/from the Garn, plus the distribution plumbing for each heat emitter, plus all the fittings, etc.
> 
> For a partial explanation of my concern I will start with P1 0013 circulator. The "sweet spot" for the 0013 as shown by its pump curve is at 18-20 gpm which occurs at a pump head of 16-18 feet (about 5.6-7.8 psi). A flow rate of 18-20 gpm at a delta-T=20 would move 180,000-200,000 btus. But my pex pressure drop table shows that at 18 gpm the pressure drop is 0.069 psi/foot, or 15.87 psi at 230', or pump head of 36.5 feet. It is clear that the 0013 will not be able to flow 18 gpm or supply btus in the range of 180,000-200,000. Actual results will be even worse because fittings, valves, etc. add additional pressure drop and pump head.
> 
> ...


Thank you for your feedback! I was hoping to hear from you as I have picked up many good things from you in other threads. To clarify:

1. Yes, the distance is one way and my runs will be long. House 1 has a 230' distance underground to the Garn and house 2 has 300' underground.

2. I estimated heat losses using the slant fin app and verified them using Taco's design software. Using 72F inside temp (where my wife is comfortable) and 18F outside temp (my region of the country is relatively mild and the coldest day is 18F or higher 97% of the time), the heat loss estimate for house 1 is 150MBU. House 2 estimate is 35MBU by the same method. Per the universal hydronic formula, a 20F dT in a non-glycol system requires 15 and 3.5 GPM, respectively.

3. I made an error by a factor of 2 estimating head loss. I used the longest distance to a load which happens to be at the highest point in the system where the 17x20 and 20x20 plenums are 21' above the Garn slab. I need an additional 50' to get to these loads. So, 230' + 50' = 280'

wrong estimate: 280' * 1.5 * 0.04 = 16.8 feet of head
better estimate: 560' * 1.5 * 0.04 = *33.6 feet of head
*
I will redraw the plan using 1-1/2" to house 1 and 1-1/4" to house 2.

My design comes directly from Page 25 of the Garn design manual and I am under the impression that zoning with circulators will handle some of the head in house 1. So the Garn pump for house 1 will effectively face (230' + 10' up into the attic)x2 = 480' of 1-1/2" to the closely space tees on the return side of the distribution system.

I am still left with the question of whether to pressurize, but I suspect more needs to be revealed taking into consideration the flow dynamics of 1-1/2" buried pipe. Thanks again for your help.
*
*


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## jebatty (Jan 1, 2016)

Looks like you have a handle on the issue I raised. I remain skeptical of the design, and I also am aware of plumbing with parallel and series circulators to handle either increase flow and/or high head situations, so it is likely there is a solution. I wish you well on your project.


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## TCaldwell (Jan 1, 2016)

Still not sure if you plan on year round or seasonal pool heating, the reason i ask is that in our last house I heated a 22,000gal gunite pool seasonly and a 750gal gunite hot tub all year and a 3500sqft house in a 6500 degree day climate with a garn 1900. The bypassed propane pool heater was 250kbtu/hr, the hot tub had a 75kbtu shell/tube hx. The hot tub draw was intermittent once at temp and not all that noticeable, the pool was a one burn a day habit from memorial day to labor day. Even if the pool had been inside, with a hot tub and house to heat during the winter, It would have needed all of 2 burns if not 3 per day, the house has ci baseboard that would do well to 130degf. Not sure how well it would have worked with hot water coil that likes 160deg plus.


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## Antman (Jan 1, 2016)

jebatty said:


> Looks like you have a handle on the issue I raised. I remain skeptical of the design, and I also am aware of plumbing with parallel and series circulators to handle either increase flow and/or high head situations, so it is likely there is a solution. I wish you well on your project.


how long did it take to ride 1496 miles? I try to do a MS Ride 150 each year and it takes 2 days! Must be quite a logistical feat to make 1496 miles. Anyway, I'm curious what part of a redesign with 1-1/2" buried as opposed the original 1-1/4" plan for house 1 raises the most concern?


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## Antman (Jan 1, 2016)

TCaldwell said:


> Still not sure if you plan on year round or seasonal pool heating, the reason i ask is that in our last house I heated a 22,000gal gunite pool seasonly and a 750gal gunite hot tub all year and a 3500sqft house in a 6500 degree day climate with a garn 1900. The bypassed propane pool heater was 250kbtu/hr, the hot tub had a 75kbtu shell/tube hx. The hot tub draw was intermittent once at temp and not all that noticeable, the pool was a one burn a day habit from memorial day to labor day. Even if the pool had been inside, with a hot tub and house to heat during the winter, It would have needed all of 2 burns if not 3 per day, the house has ci baseboard that would do well to 130degf. Not sure how well it would have worked with hot water coil that likes 160deg plus.


The kids get about 3 or 4 months to swim in 85+ water with no additional heating, just plain old sun. I'd like to extend it to 8 months if not the entire season. We rarely get temps down to 20F and for no more than a few days. Normally, we have 30-40F days mixed with warmer temps all winter. I'm not too familiar with heating degree days, but from what I briefly googled it appears HDD here is 3000. I have unlimited amount of wood and I enjoy working on the farm so multiple burns/day won't be a problem, especially as the kids get older and hopefully they will enjoy it, too!


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## leon (Jan 1, 2016)

Antman said:


> I'd like to get feedback on my proposed Garn hydronic design from all the experts out there! I tried to simplify the design by keeping it unpressurized. I plan to heat 2 houses, a 25,000 gal salt pool, and a 500 gal hot tub. My focus at this time is on the larger of the 2 houses. The smaller home can be delayed until next year. We are completing the construction of a carriage house which houses a Garn 2000 and its location was strategically chosen because it is between the 2 houses and on one of the highest locations on the farm which is 3' above the bottom floor of both houses.
> 
> While I want to make it simple, I am open to suggestions about how to make it better even if I have to scrap the entire design. Fortunately, I have my wife's support and I'd like to keep it that way by getting it right on the first attempt . I was hoping to draw from all the wisdom from those who post on this site so I can hopefully provide insight for others who might make the plunge and become more self-sufficient.
> 
> ...


 






=====================================================================

Hello antman,

Am I correct in assuming you have invested in Garn 2000 already or are you are just putting pencil to paper????????

Do you have a large source of firewood and the time and equipment to process the firewood?? Or will you be buying fuelwood?

Before you shoot yourself in the foot and make mistakes I would like you to invest in a pair of books by Dan Holohan.
They can be purchased from AMAZON or Dan Holohan books,

The Paperbacks are "Pumping Away" and Classic Hydronics. Please do not start anything until you read and reread these books several times. You have to remember that these specs. given to you are written by engineers for engineers and arechitects.

Dan writes all his books for the layman from all the experience he has gained from working in the plumbing and heating business as a plumbers helper, factory representative, wholesale plumbing house representative, and plumbing problem troubleshooter for commercial steam and hydronic heating working with huge heating loads and small ones.

Dan writes from the point of experience and makes plumbing for hot water heat and steam heating to understand for the home owner and commercial business owner easy to understand with no difficulty and he makes reading about plumbing fun along the way.

---------------------------------------------------------------------------------------------

I would like you to send your sketch to Dan Holohan and tell him I sent you by putting "LeonZ sent me to you" in the subject line.

Dans email is dan@heatinghelp.com

Have you considered a simple anthracite coal stoker boiler in anyway for the heating load you are planning?
You do not need 2,000 gallons to do this as designed by you if you use an anthracite coal stoker.

The thing is your not taking advantage of gravity and your simply trying to slap it around.

Are you going to invest in the Oxygen Barrier Pex and the $15 per foot insulated Pex tubing for the hot water delivery and return loop?? If not wad up your drawing and burn it.

You need guidance.

You don't need 2,000 gallons of water to do this as coal stoker boilers are used in huge green houses, make hot water for commercial laundromats and heat many large homes and multiple residences using one coal stoker boiler for hot water hydronic heat and domestic hot water.


I am getting away from burning wood after 33 years and I am having a coal stoker installed on the 4th of January and I wish I had it done 33 years ago.


Just remember you have a plumbing problem you want to solve and look at it that way and that way only.

Several things to look at:

Will your zoning and local plumbing code permit this to even be done?

It may not as each residence is not connected physically even though it is rural and assuming it is an active agricultural enterprise.

Heating more than one home with a common heating plant is considered a Regulated Utility in some states-
In North Dakota you cannot heat more than three homes using a common heating plant and unless
the state law has changed it is still in force.

Are you looking 30 years down the line to where these houses may be sold? It may be a huge problem with one main heating source connected to all of them for heating and the eventual sale of the properties.

In the State of New York in Tompkins County they have a screwed up zoning area(one of two in the nation apparently) where the Town of Lansing has two separate and distinct zones, Wherein  one set of zoning laws is for the Village of Lansing and another set of zoning laws for the Town of Lansing exist.

If you have no access to anthacite coal for heating locally I think that you are going to find that a trenched geothermal system(four to six feet deep) for each place will cost you much less money to invest in if you have lots of land to to install it on and the heating and Domestic hot water loads will be much much easier take care of.


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## Antman (Jan 2, 2016)

leon said:


> ================================================================================================
> 
> Hello antman,
> 
> ...


The main thing I heard you say is that I need guidance which is why I'm reaching out to the community for feedback before committing to the overall Garn pump/buried pex/distribution system design. I already have the Garn 2000 on a slab in a new barn we are finishing. My neighbor and I are processing a pile of trees the loggers left last year. It looks to be at least 50 full cords of mostly hickory, red oak, white oak, as well as other decent mixed wood like ash. The only thing we are throwing to the side seems to be sweet gum. I've estimated burning 7 and 3 full cords per year for house 1 and 2, respectively. My neighbor says he burns 3 full cords per year and his house is very similar to house 2. Code enforcement has already given me approval for the project.

I did order the books you suggested and look forward to reading them. And, I emailed Dan the new design with larger lines and told him you referred me to him.

As far as I know, no one in West Tennessee burns coal. Perhaps they do in East Tennessee closer to West Virginia. It seems to be either NG in the cities or LP in the rural areas for West Tennessee. LP went up to $3.70/gal down here last year when the cattle needed warming up north. Needless to say, cordwood is beginning to catch on around here. I am curious why you switched from wood to coal? For me, I enjoy the workout and the otherwise quiet outdoors. We have an endless supply of large trees on our farm. Not ever going to sell it, would love my kids to take it over when my time is up.

BTW, the reason I chose the Garn is I wanted a simple, unpressurized system with integrated storage and I wanted to maximize the time between burns. Also, house 2 will be able to take advantage of radiant floor heating which seems to be the best way to heat. We spent $7,000 on LP last year between the 2 houses so I justified being able to pay off this install over 5 years. Of course, that clock doesn't start until the system is up and working. It would be nice to heat this season, but the clock might have to start with heating the pool in the spring

I'm glad you mentioned geothermal. I have a 5 acre pasture by the Garn Barn and was curious if anyone knows how I should stub out the garn manifold in the event I ever want to cool in the summer?


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## maple1 (Jan 2, 2016)

I think cooling with Geo in the summer would need ductwork and be a completely separate system. Don't see how that can be tied to the Garn system. Everyone I know who has done Geo has ended up with higher electric bills than they were expecting.

Have you costed out underground piping yet? That is going to be huge here. The right stuff is in the area of $15/ft, I think - and you don't want to use the wrong stuff.

I was looking for someone to jump in about your elevation differences - I am kind of suspect about that, but don't really know.


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## jebatty (Jan 2, 2016)

Antman said:


> how long did it take to ride 1496 miles? I try to do a MS Ride 150 each year and it takes 2 days! Must be quite a logistical feat to make 1496 miles.


 Thanks for the interest -- 23 days of riding, 25 days total. Shortest mileage day was 23 and longest was 97. Average/day was 65 miles. Temperatures ranged between a low of 28F (two mornings) and a high of 94F. The trip was solo, self-supported. Bicycle plus packs, gear, food, water was about 105 pounds. An amazing adventure for a 66 year old guy. This link covers a quick summary of most of the trip: Rolling

I am narrowing down on a destination for another trip in 2016.


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## leon (Jan 2, 2016)

maple1 said:


> I think cooling with Geo in the summer would need ductwork and be a completely separate system. Don't see how that can be tied to the Garn system. Everyone I know who has done Geo has ended up with higher electric bills than they were expecting.
> 
> Have you costed out underground piping yet? That is going to be huge here. The right stuff is in the area of $15/ft, I think - and you don't want to use the wrong stuff.
> 
> I was looking for someone to jump in about your elevation differences - I am kind of suspect about that, but don't really know.


 



============================================================================

Hey Maple One, Happy New Year to you and all on the forum.

It was a tad late when I posted and handfiring the coal boiler.
I barely touched the Pex issue. and did not do the formulae for
the head loss issues and the points of pressure change in his
system as it was 2 in the morning when I waddled to bed after
loading the boiler.

I will do the number crunching for that when I waddle back from
my fathers place if no one jumps in before that as it can go two ways
with circulators in each residence pumping up hill with a steel expansion
tank in both homes in the highest location being the attic and a third
for the ceiling above the Garn boiler for a heat exchanger used to transfer heat
to the two homes heating loops.


He is going to have three points of pressure change not including
domestic hot water loops(if used) being home number one,
home number two and the circulator used at the GARN if used
there BUT having the circulators in the homes is easier to deal with
as no pumping down will will occur and he will have little if any
water hammer pressures to worry about.

Bladder tanks lose one PSI annually as a rule and steel expansions
have zero issues period as they have only water in them with the
airtrol valve that controls the air bubbles by slowly allowing them
to enter the path into the expansion tank. after the hot water
enters the steel expansion tank it cools and allows the air bubbles
to be absorbed into the cooler water.

The steel expansion tanks do not have any moving parts they simply take advantage of gravity to the fullest extent and you can have very large expansion tanks or a number of small ones plumbed in parallel with a common header pipe to do wonders for heating and cooling/chilling duties with small circulators.

As I said a steel expansion tank has to be above the boiler and you
dont have to worry about them ever unless you drain the system
wherein they have to have the airtrol  vent opened up to allow
them to drain before the water is drained out of the system.

He will need at least two steel expansion tanks to allow the
circulators to operate. preferably he will have a circulator in each
residence as the steel expansion tank will have to be higher than the
Garn.

Folks are going to disagree with me about that but if you use the simplicity
of a steel expansion tank combined with A LARGE ENOUGH heat exchanger you
will not need monster size pex for this as the smaller 3/4" insulated $15.00 per foot pex
only loses 1 degree per one hundred feet. 

The more water the better the flow control in his case and there will be no little to no issues with water hammer as he will be able to keep the water pressure at atmosperic or a little more. you are not creating a great deal of pressure with the water you are just circulating it from the homes to the garn barn if you use a heat exchanger from the garn to the two house heating loops.


Just an FYI; the larger the steel expansion the greater amount of water you have to to create the water weight in the system and reduce problems with air bubbles and you will have them unless you install Power Purge valves/boiler drain valves that will allow you to push the air out of your systems at each residence at filling and also using the boiler drains on each feed and return for each circuit which eliminates chasing air bubbles 
as the air bubbles would be forced downhill to the hose you are using to vent the specific heating loop/home with very little effort.

The main benefit is that you are not pumping against the water weight of the GARN as the water weight of the GARN stops at the heat exchanger with a separate circulator to move hot water through the heat exchanger used for the two heating loops.

As far a circulators go you don't need large diameter pex as long you do it the right way with check valves in the circulators to push the water up hill to the Garn Boiler. Besides that the larger pex is going the strip more heat from the thermal mass of the water in the Garn 2000 and you have to think about that as you will have to fire the garn more often or keep a fire going with it.

You can only push so many BTU through a given pipe diameter so 3/4 baseboard releases 540 BTU of 170 degree water per foot.


SO if you take my circulators for example the B+G NRF25's being simple numb dumb three speed pumps at speed three setting each one will circulate 20 GPM at 18 feet of head.

If you tie in a second B+G NRF25 that's another 20 gallons per minute for a total of 40 gallons per minute NOW understand that 60 minutes times forty gallons per minute is 2,400 gallons in one hour of circulation.

In forty five minutes you will have moved 2,000 gallons of water and returned the same amount of cooler water back to the Garn and you have cooler water to heat up again and your already behind
the proverbial 8 ball.

If you use 3/4 pex and four gallons per minute from each home you will only be moving 480 gallons of cooler water back to the heat exchanger per hour to be reheated to 170 degrees if and only if you use a  pair of 3/4 pex loops to the heat exchanger that be connected to a circulator that moves hot water from the boiler to the heat exchanger that is being used to heat the two 3/4 pex loops.
(your entire mass of hot water (2000 Gallons) will be exchanged every 4 hours rather than every 45 minutes using larger circulators and pex tubing.

Using a lower water temperature shed heat at lower rate but there is less heat loss
per linear foot. 140 degree water releases 340 BTU per hour per linear foot of 3/4 baseboard.

I need you to understand that water to air coils in your duct work are huge energy hogs and can strip the BTU's from the water like a vacuum as all it is is a RADIATOR so keep that in mind please and they same applies to large PEX and dont let anyone say otherwise because the coils will strip the heat from the water and return very cold water back to the Garn if you go that route without a heat exchanger in the Garn barn.

The other thing is that if a system bypass loop is used you can keep the Garn boiler water hotter at all times

============================================================================

Your going to run out of hot water sooner if you use larger diameter Pex and then you will be burning around the clock loading may more times per day.

NOW rounding off the Pex you have 1,100 feet in total pex footage to and from both residences.

If 3/4 pex is used you have 1.84 gallons per hundred feet times 11 gives you 20.24 gallons in the pipe loops in total with 3/4 pex per hundred feet.

I hope you see where I am going with this as you can use lower temperature water to heat the homes and keep the boiler hotter to provide a faster recovery rate for the two 3/4 inch loops. The circulators will run longer but they dont care.

If you intend to use the 1 1/4" Pex your going to need much more hot water and a used surplus insulated 8,000 gallon railroad tank car body will be the only solution as long as a system bypass loop is used to heat the 8,000 gallons in the surplus insulated tank car body by using the 2,000 gallons in the Garn boiler constantly circulating between the tank car shell and the Garn for the insulated surplus tank car body to act as a buffer tank for the garn boiler and the heat exchanger if used.

AS long as a LOW WATER CUTOFF is used in the 2 lower boilers the system will be better protected with the water volume limited to the volume in the pex loop from the heat exchanger loop+ the boiler+and the water in the steel expansion tank if used.

By drawing the hot water off the top of the boiler you are pulling the air bubbles out and they are easier to purge with a module that has a standpipe with a boiler drain in the top of it( if your current boilers do not have an internal baffle and an air vent in the steam chest.

Your going to be chasing air bubbles if you cannot purge each loop individually.

Unless you use the good 3/4" pex at $15.00 a foot FOR ALL underground lines your going to have to keep the lawn mower heated and ready to work.

Cooling gets little more involved only because you have 5 acres to use and if each home has a straight shot to it in a 1,000 foot loop with the lines 50 feet apart a smaller geo unit would work as the ground temperature would be as low as 52 degrees at 4 feet deep.

BUT that is not saying you could not run a longer loop if you have the room if you can clear the land.

Alternatively a deep and narrow in width pond long in length could be dug and lined with a one piece liner to use as a heat exchanger for chilling spiral loops of black PVC that is held down with cinderblocks.


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## leon (Jan 2, 2016)

Antman said:


> The main thing I heard you say is that I need guidance which is why I'm reaching out to the community for feedback before committing to the overall Garn pump/buried pex/distribution system design. I already have the Garn 2000 on a slab in a new barn we are finishing. My neighbor and I are processing a pile of trees the loggers left last year. It looks to be at least 50 full cords of mostly hickory, red oak, white oak, as well as other decent mixed wood like ash. The only thing we are throwing to the side seems to be sweet gum. I've estimated burning 7 and 3 full cords per year for house 1 and 2, respectively. My neighbor says he burns 3 full cords per year and his house is very similar to house 2. Code enforcement has already given me approval for the project.
> 
> I did order the books you suggested and look forward to reading them. And, I emailed Dan the new design with larger lines and told him you referred me to him.
> 
> ...


 
============================================================================

I decided to switch to coal stoker for a lot of reasons.

100+ year old former one room house, poorly insulated and huge indbreaks/shelterbelts
over 70 feet high.

Very little space with no basement and pellet boilers are more expensive than a coal stoker boiler


The former owner lived in home seasonally and hid all the problems-the home was purchased in 1978 before the laws changed to protect the purchasers rights when buying a home.


Lousy draft even though I live 1,140 feet above mean sea level
Age of 61.
My wifes age of 61.
The wood supply.
Always tired of tending the boiler until 2 or 3 in the morning.
Looking forward to saving $110 a month or more and having more time.  
I have a 3-5 year coal supply on hand.
Rice coal provides more usable heat per ton than cord wood or kerosene.
Eliminating the rats nest of plumbing used as system.
Temperature balancer between the two boilers.
Eliminating the second circulator for temperature balance between boilers.
Eliminating the separate kerosene boiler by investing in a Keystoker KAA-4-1 dual fuel unit
Having more hot water in the boiler 51 gallons including the steel expansion tank, heating loop and boiler.
Saving money on electricity by eliminating the second circulator

Cost of heating Oil-Here between 110.00 to  303.00 a month depeding on market conditions and the cost of oil will go back up.

Poor service from my heating oil company:
I have been left high and dry several times with having,
run out of kerosene while on their budget plan for oil deliveries,
Late night burner failures and being told that my burner cannot be serviced
because they no longer make parts for the specific RIELLO burner
and having replaced two of them when It was NEVER NEEDED EVER!
My desire to eliminate the as my supplier PERIOD.



No access to natural gas nor do I need it.
Low propane cost for hot water less than 25.00 per month

The locals around here buy logs at $33.00 a ton and charge over $200.00 a cord delivered in some bad years  and the processed wood is poor and many of the rounds/splits  have to be resplit.

I had enough when I fell on the ice made from the commercial firewood splitters heat
from the exhaust and hydraulic tank I owned had a habit of creating pools of water from all the heat it created and when I used the salamander to preheat it and then froze up.

One late night I was done splitting wood and slipped on the ice that was created and I thought I had a facial fracture I was bleeding so much and creating snot rockets and I spent five hours in the local ER and I decided I had enough after 31 years.

The anthracite coal fields are only 3-4 hours south of me on Route 81 and I can buy bagged coal at a very reasonable price.


I would have installed a Van Wert Anthratherm coal stoker at the time 33 years ago if I could have afforded the installed price but the coal and wood boiler install was 2K less.



Live and learn.

Be sure to install a system bypass loop to keep the boiler water hot and reduce cycling.

Dan Holohan covers this extensively in his books for fossil fuel boilers and it also works for coal and wood boilers and dont let anyone tell you differently.


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## jebatty (Jan 2, 2016)

Antman said:


> Anyway, I'm curious what part of a redesign with 1-1/2" buried as opposed the original 1-1/4" plan for house 1 raises the most concern?


 My focus as you probably can tell is mostly about the math plus efficiency. Know the heatload, determine an acceptable pump head, size pipe and fittings accordingly, pick an efficient circulator to deliver the gpm at needed delta- T.

Also place unions and valves to isolate all components that may need future service/replacement. Install sensors to monitor all important points. This will allow you to fully understand how your system actually operates/performs. 

Lots more about all of this. Asking specific questions is better than generalized questions.


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## leon (Jan 3, 2016)

Hello Antman,


Please understand I only want to help you.

With regard to hot water for heating
you have to have a complete grasp of basic terms.

You are using Circulators not Pumps.
The terms are exchanged too often and too freely.

A circulator with a check valve cartridge is better for
moving chilled water for cooling or hot water for hydronic
heating long distances or uphill. 

There are five terms I want you to understand fully that you need to understand fully as they are never dealt with completely by many sellers of heating systems. 

1. Total Head Without Flow/Shut off Head

2. Total Head Without Flow

3. Suction Static Head

4. Friction Head

5. Discharge Static Head


Using a single heat exchanger for both loops "in the carriage house"
with a small circulator will reduce the possibility of leaks on the
down hill side as the amount of water will be limited to the total water
volume in the two homes and only the two homes as the all heating
water stays in the carriage house.

If you have a buffer tank in the carriage house you have more hot water
at all times, the more hot water the better.
You can use the buffer tank as a sealed tank that can feed the heat exchanger
that is shedding heat to the two heating loops.

----------------------------------------------------------------------------------------------

Using steel expansion tanks in the attic in both homes provides you with the
back pressure in the system that will aid the small circulators with check valves
in pushing the water uphill with very little effort.

You cannot use a steel expansion tank and a bladder tank in the same system as the circulator will be confused and have no point of pressure change. AND the automatic air vent will suck all the water out of the steel expansion tank.

You need to have valves to separate the fossil fuel boilers from the garn wood boiler loops and shut them off when you use the fossil fuel boilers.      

Be completely comfortable with the above terms
before you make any rational decisions for the
heating load you have and understand fully that you
will have more hot water to use if you use 3/4 inch Inside Diameter
Pex Tubing.

Your going to waste money and heat if you do not use the
insulated oxygen barrier pex tubing that costs $15.00 per foot
as it only loses one degree per 100 foot of length from the boiler
to the heating load and retains more heat returning to the heating
appliance-meaning the Garn Boiler. And your going to need to use
the lawn mower or the rotary cutter over both PEX pipe runs to the
carriage house. THE less expensive wrapped insulated PEX loves water.


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## Antman (Jan 3, 2016)

Just wanted to say thanks to everyone for the responses and Happy New Year! As I expected, I have some new things to think about. I've heard it before, "There's more than one way to skin a cat." And, I am taking things slow because I want to give myself the best chance of success even if I don't heat at all this season. I'm going to call Garn and let them know my progress and see who they think I should hire for the design based on my personal situation. Fortunately, I have a father-in-law and grand-father-in-law who have been general contractors their entire lives and want to be involved with other installs if this one goes well. My job, other than being the fetcher and finder-of-the-board-stretcher, is to get the design right. It is clear to me that that requires more experience than I have.

Until then, I guess I'd like to say that I feel Logstor could be the best preinsulated offering. I did get a quote on 1-1/4 and 1-1/2 dualpex and I think it's overpriced. For my long runs it won't be the best option now. I have been back and forth on the pros and cons of preinsulated vs. trench-and-foam. For my setup, I think a modified trench-and-foam: Spray 2-component PUF in a form made of XPS board glued together with 1-component PUF, screws added for additional rigidity including spacers to hold lines in place. Coat of bluemax. Lay down fiber. Additional bluemax layers. 6mil plastic glued back onto itself with as much bluemax and a single layer of fiber as you can get between the overlap making the 6mil joint water tight. We did a materials test and the results look promising. I was surprised how much of a difference the fiber makes. If you are willing to give up on fighting the PUF aging process, I do not see how preinsulated offers any advantage in terms of water resistance. In fact, the logstor jacket may not have the ability to reseal punctures as well as the blueMax with fiber seems to offer. If anyone has a scrap of logstor I'd love to perform that experiment.


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## leon (Jan 3, 2016)

Spray foaming trench lines gets very expensive and the insulated tubing is more forgiving with ground shifting and settling over time

Thats the major reason for replacing the trench dirt with mason sand or concrete gravel sand and installing pipeline danger tape a foot above it BTW.

Placing the tubing below the frost line pays you it does not cost more as a gravel sand filled trench is safer on all piping.

Even burying the tubing on one side of a shallow trench with a foot of sand above it will pay you big dividends in longevity and cost less per foot of excavation expense  as you can rent a trencher and fill the trench with sand below the tubing and then to the ground surface.


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## Antman (Jan 5, 2016)

leon said:


> Spray foaming trench lines gets very expensive and the insulated tubing is more forgiving with ground shifting and settling over time
> 
> Thats the major reason for replacing the trench dirt with mason sand or concrete gravel sand and installing pipeline danger tape a foot above it BTW.
> 
> ...





leon said:


> Spray foaming trench lines gets very expensive and the insulated tubing is more forgiving with ground shifting and settling over time
> 
> Thats the major reason for replacing the trench dirt with mason sand or concrete gravel sand and installing pipeline danger tape a foot above it BTW.
> 
> ...


OK. I just realized that both Logstor and the Garn Design Manual are using ID for underground pipe whereas the ASTM sizing for other pex such as uponor which I plan to use is sized closer to OD. This changes things a bit.

So, for me to get 15 GPM when all 3 of my WTAHX call for heat (20F dT), the smallest logstor I should use is 1-1/4" dualpex (1.28" ID) for my underground run of 230'. I would need to use 1-1/2" uponor for the distribution pipe which has an ID of 1.24". This should be able to provide 15GPM to supply my 150MBH load when all WTAHX call for heat at the same time. However, I likely would not be able to consistently get enough BTUs for DHW. I also would not be able to heat the pool and spa all winter. While the house would likely be able to get nice and toasty, I would be limiting my Garn from delivering the 325MBH that it is capable of putting out.

On the other hand, if I get 1-1/2" logstor dualpex (ID1.6") for the underground pipe and 2" uponor for the distribution pipe (ID1.6") I could get 270MBH if all loads have similar 20F dT. In this scenario, not only could I get the 15GPM for all 3 WTAHX calling at the same time, I could get an additional 12GPM for DHW/pool/spa heating in the coldest of weather. The cost of going this route with the larger underground/distribution combination is a lot, but, as I've heard before, it's a one-time cost and will make use of the Garn 2000's full potential.

Now that this is clear to me, I think it makes more sense to put a FPHX by the Garn and pressurize the system on the underground/distribution side of house 1. Another option is to perform the modified trench-and-foam I described earlier with 2" underground pex (1.6" ID) and 1-1/2" distribution pex (1.6" ID). Either way, the circulators will work more efficiently because there will be less of a pressure drop, not to mention avoiding corrosion of cast iron pumps, dezincification of brass, etc.

I will redraw accordingly and post later tonight.


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## maple1 (Jan 5, 2016)

That was some of my feeling also on the pressurized topic - but I didn't really know so was waiting to see if you'd get more input on it.

And, to put it in 'For Dummies' talk on another thought on it - I was also thinking your water wouldn't stay in your boiler (& system) with the rest of the system so far above it. I could envision it running out of the top of the boiler.

I think with that much underground I would heavily consider spraying in trench - depending on what kind of a deal you can get from a local spray foam guy. Usually the cost/foot might come down a bit with more footage to do.

Also one more on your DHW comment - DHW is a very small part of a heating load compared to what your other HXs & houses will be using. So I would expect you could heat your DHW pretty well no matter what else you do. I can heat our DHW for a month with resistance electric for what it would cost to heat our house for only one day the same way. Unless of course you are rather off the charts with your DHW use.


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## jebatty (Jan 5, 2016)

That ID indeed is important, glad you noticed that. 

Keep in mind that although the Garn WHS2000 carries a 325,000 btuh maximum output, it probably is unrealistic to expect to see that for extended periods of time. My rule of thumb for gasification wood boilers is that average output over a burn is about 70% of rated output. Also keep in mind the Garn is best operated in batch burn mode: burn a load (or a couple of loads), let the fire go out, clean the ash and dead coals, and then the Garn is ready for another batch burn. 

A couple of years ago I did extended and intensive data logging on a Garn WHS3200, rated at 700,000 btuh. Over an 18 hour period I was able to keep the Garn fueled at the rate of 100 lbs of wood per hour, and by the end of the period the Garn had to be allowed to burn out because the firebox bed was loaded with coals and additional wood could not be added. Also, actual output over the 18 hour period was measured at 500,000 btuh, which is almost exactly 70% of the rated output. 

Also keep in mind that if you need consistently very hot water, 160F minimum, even as low as 140F minimum, your Garn will need to be fired pretty consistently to provide that hot water. That also would be true of other gasification boilers. If you can use water down to 120F or lower, then you have a lot more flexibility in firing your boiler. Of course, heat loads play a big role in this.


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## leon (Jan 5, 2016)

I wish I could say definitely that your going to have enough hot water but you are going
run out of hot water unless you the 3/4 pex in two loops passing through a water to water heat exchanger in the carriage house.

Saying that I believe your going to run out of hot water quickly with that pex ID as you will be pushing 900 gallons per hour when calling for heat where you will have a complete exchange in 2 hours and 16 minutes+-.

The laws of thermodynamics are against you unless you use 3/4 pex for both loops and circulate 8 gallons per minute "in total"  with a water to water heat exchanger and in  combination with a 140 low and 160 high aquastat temperature setting.
=======================================================================
Quoting from Danholohans book "Classic Hydronics"  from Page 17;


Quote:

" When your sizing that new boiler"


Boiler manufacturers rate their boilers they use a bunch of terms to do this.
Let me take a minute to explain (or at lest try to explain) what thats all about.

When you look at a boiler manufacturers catalog you'll see that there are seveveral types
of ratings for each boiler. Theres the Input rating, The Gross Output rating, which they call the
DOE Heating Capacity nowadays (DOE is the U.S. Department of Energy) and then there's the
Net Output rating. You pick one or another to size a boiler. But are you sure you picked the right one?

To make things even more confusing, some of the ratings are shown as Btuh (British Thermal Units per Hour),
while others are listed as Square Foot Equivalent Direct Radiation or EDR for short (and here you'll find different numbers for water and steam boilers). Then we have this other column for Gallons Per Hour, which applies to fuel oil,
and another for Therms, which applies to gas.

OKay here is whats going on. You have three basic columns. First theres Input, Thats where you'll probably find the ratings in Gallons Per Hour or Therms because this column has to do with fire. What you're seeing here is the amount of heat that the fire is putting into the boiler. You PUT the fire IN and thats what they call Input.

But, not all the heat that enters the boiler winds up in the water. Some of that heat goes up the chimney and is lost forever. There's alos some more heat lost through the boiler's jacket, but this is one of those vague areas because if the boiler is in the house, can we really say that the jacket losses are gone for good?. And there are some boiler manufacturers who will tell you that thier jacket insulation is so fabulous that British thermal units hardy ever choseto leave that way, but whatever.  

Next, we get to Gross Output (or DOE Heating Capacity). Gross is what's left over after the boiler has suffered the heat loss up the cminey and through the jacket. Now this term can be a bit confusing because Gross usually implies that you're dealing with the whol enchilad, as in Gross Income (which means before taxes, right?). But in the world of hydrononics  Gross means, "whats leftover" instead of "what you start with." Or to put it another way Gross means "after taxes." "Taxes" in this case, being the price you pay when you send heat up the chimney and through the boiler jacket. Just remember this:
Gross Output is the amount of heat that rideson the water that's flowingout of the boiler. It's the heat that's available to the whoel system(and maybe that's why they call it Gross). 

Ready for the next factoid? Here goes: The difference between the the Input and the Gross Output represents the combustion efficiency of the boiler. For instance, if a boiler has an input of 200,000 Btuh and a gross output of 160,000 Btuh, that boiler would be running at 80% combustion efficiency. It's not that hard to figure this out. Just divide the larger number into the smaller number and then multiply the result by 100 to get a percentage.

Unquote:


This is the reason I mentioned the surplus insulated railroad tank car body as a buffer in your installation.

This buffer would let you heat the water in the buffer tank at a high temperature and the Garn would continue to circulate 4 gallons per minute of very hot boiler water into heat exchanger for the the buffer tank and have a complete exchange in 200 minutes.

When the buffer tank comes up to temperature, lets say 160 degrees that 8 thousand gallons would be able to shed the heat through the heat exchanger that is shedding  the heat to both loops at 8 GPM in total for 1,000 minutes or 2 hours and five minutes. The amount would probably be much less once the buffer tank comes up to temperature of course becuase the buffer tank is insulated and sealed from heat loss.  

surplus insulated tank cars are available for sale and you can sell the trucks and axles to defray some of the cost.

Buying a big buffer tank "Uninsulated and new will cost much, MUCH more money than a surplus insulated railroad tank car at the end of its service life which is typically 40-45 years of service. 

I want to help you not hinder you, I want you to suceed not fail.


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## maple1 (Jan 5, 2016)

leon said:


> I wish I could say definitely that your going to have enough hot water but you are going
> run out of hot water unless you the 3/4 pex in two loops passing through a water to water heat exchanger in the carriage house.
> 
> Saying that I believe your going to run out of hot water quickly with that pex ID as you will be pushing 900 gallons per hour when calling for heat where you will have a complete exchange in 2 hours and 16 minutes+-.
> ...


 
Where & how did you come up with 900 gallons per hour & 3/4" lines?

EDIT: Nevermind on the 900 gph, I see that in the 15gpm mentioned earlier.


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## maple1 (Jan 5, 2016)

I'm kind of wondering about those heat loads.

150,000 btu/hr seems like a lot for a place that doesn't get colder than 20f.

From my burning habits here the past couple of years, I think I'm in the area of somewhere between 500,000 & 600,000 btu per day. It was -18c here this morning (0°f). It is now -12c (10°f). I'm in a 20 year old 2700 sq.ft two storey (plus 1500 sq.ft. basement), on an open hilltop.

Unless I missed something along the way...


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## Antman (Jan 6, 2016)

maple1 said:


> That was some of my feeling also on the pressurized topic - but I didn't really know so was waiting to see if you'd get more input on it.
> 
> And, to put it in 'For Dummies' talk on another thought on it - I was also thinking your water wouldn't stay in your boiler (& system) with the rest of the system so far above it. I could envision it running out of the top of the boiler.
> 
> ...


If I can find 300' rolls of 2" barrier uponor or equivalent 1.6" ID I probably will trench and foam. It would take quite a bit longer but I have the patience and manpower to see it through. I am confident we have a water tight solution with bluemax if it comes to that. Otherwise, I may just have to bite the bullet and buy logstor preinsulated dualpex 1-1/2" (1.6" ID). Admittedly, logstor would be much easier to install and perhaps last longer and minimize the aging of the PUF with their special membrane under the HDPE jacket.

Bluemax is a barrier to radon but I couldn't find a way to compare diffusion coefficients between radon and cyclopentane which is the gas in Logstor PUF that equilibrates with atmospheric air in the absence of a proper barrier. I'm not sure what the insulating gas would be in the PUF I can resource. All I know for sure is radon is an element and cyclopentane is a C5H10 molecule so perhaps an elemental radon barrier such as bluemax would also be a barrier to a larger cyclopentane molecule assuming molecules are generally larger than elements. Unless someone can provide a definitive reference, I'd just have to assume any PUF I have sprayed would likely age and lose 15% of its initial insulation value. I think spraying thicker than logstor's thickness could offset this loss in R value. What is important is ensuring water tight underground lines which I will have to demonstrate to everyone using XPS with bluemax-impregnated fiber when I get the time.


----------



## Antman (Jan 6, 2016)

maple1 said:


> That was some of my feeling also on the pressurized topic - but I didn't really know so was waiting to see if you'd get more input on it.
> more complicated but seems worth if for less corrosion
> 
> And, to put it in 'For Dummies' talk on another thought on it - I was also thinking your water wouldn't stay in your boiler (& system) with the rest of the system so far above it. I could envision it running out of the top of the boiler.
> ...


is there a difference b/w resistance electric and local utility electric? Wouldn't necessarily apply at this time until we get house 1 done and start on house 2 later which has electric DHW. House 1 has 3 50 gal LP DHW tanks. Kids take hot baths every night in large jacuzzi tubs and wife and I take reasonably long showers each day, kids will probably take longer showers as they grow up. Hot water taps run left open frequently as we do not have hot water recirc in place at this time...


----------



## Antman (Jan 6, 2016)

maple1 said:


> That was some of my feeling also on the pressurized topic - but I didn't really know so was waiting to see if you'd get more input on it.
> more complicated but seems worth if for less corrosion
> 
> And, to put it in 'For Dummies' talk on another thought on it - I was also thinking your water wouldn't stay in your boiler (& system) with the rest of the system so far above it. I could envision it running out of the top of the boiler.
> ...


is there a difference b/w resistance electric and local utility electric? Wouldn't necessarily apply at this time until we get house 1 done and start on house 2 later which has electric DHW. House 1 has 3 50 gal LP DHW tanks. Kids take hot baths every night in large jacuzzi tubs and wife and I take reasonably long showers each day, kids will probably take longer showers as they grow up. Hot water taps run left open frequently as we do not have hot water recirc in place at this time...


jebatty said:


> Thanks for the interest -- 23 days of riding, 25 days total. Shortest mileage day was 23 and longest was 97. Average/day was 65 miles. Temperatures ranged between a low of 28F (two mornings) and a high of 94F. The trip was solo, self-supported. Bicycle plus packs, gear, food, water was about 105 pounds. An amazing adventure for a 66 year old guy. This link covers a quick summary of most of the trip: Rolling
> 
> I am narrowing down on a destination for another trip in 2016.


For anyone who doesn't ride out there, that is one hell of an impressive ride! I'm in pretty good shape, and I cannot fathom how I could ever pull that off without riding many years almost daily.


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## Antman (Jan 6, 2016)

jebatty said:


> That ID indeed is important, glad you noticed that.
> 
> Keep in mind that although the Garn WHS2000 carries a 325,000 btuh maximum output, it probably is unrealistic to expect to see that for extended periods of time. My rule of thumb for gasification wood boilers is that average output over a burn is about 70% of rated output. Also keep in mind the Garn is best operated in batch burn mode: burn a load (or a couple of loads), let the fire go out, clean the ash and dead coals, and then the Garn is ready for another batch burn.
> 
> ...


So 70% 0f 325MBH is 227.5MBH. In the Garn Design Manual I see 1.28ID and a 30F dT at 15GPM can deliver 225MBH which could be performed with 1-1/4" logstor. The problem is that there are not a lot of WTAHX from which to choose and I believe most of them have 20F or less dT. Is anyone aware of WTAHX with 30F dT? If not, I guess I'm still looking at 1-1/2" logstor.


----------



## Antman (Jan 6, 2016)

I really appreciate everyone's feedback and support!

Thank you, thank you, thank you!

It is helping me clarify some of my own preconceived notions I have developed after reading the Garn Design Manual. I'm looking forward to reading the books from Dan H. I'm hoping to get more clear how 3/4" lines and/or the 8000gal tank car could work. I can't see how enough BTU's could get underground to satisfy the 150MBH load with all WTAHX calling for heat at the same time. Is the buffer tank the key to 3/4" lines working and, if so, I suppose it has to be adjacent to house 1 and not the Garn barn? If it could go by the Garn barn that is doable but I can't realistically think of a way to put an 8000 gal tank car next to house 1. And, once all 8000gal are up to 160F, am I correct in thinking it extends my time between burns four-fold?

Please forgive my lack of experience drawing diagrams, but could you mentor me on how the 3/4" design needs to be altered?


----------



## maple1 (Jan 6, 2016)

Antman said:


> is there a difference b/w resistance electric and local utility electric? Wouldn't necessarily apply at this time until we get house 1 done and start on house 2 later which has electric DHW. House 1 has 3 50 gal LP DHW tanks. Kids take hot baths every night in large jacuzzi tubs and wife and I take reasonably long showers each day, kids will probably take longer showers as they grow up. Hot water taps run left open frequently as we do not have hot water recirc in place at this time...


 
No. Well, sorta. Resistance electric heat uses local utility electric to heat water via elements. As opposed to say a heat pump, which uses utility electric to heat via refrigeration techniques.

My DHW tank heats my DHW in the summer the same way as my backup electric boiler heats my house when there is no wood fire going on. Only difference is the DHW tank uses one 4500w element at a time, whereas the electric boiler has 4 of them going, as needed.

You do have more hot water usage than we do. Up until last summer, we had 2 adults & 3 teenagers. No baths but showers every day (usually). But overall, with checking out power bills & heat useage, our space heating demand is about 30x what our DHW demand is, in kwh. Roughly estimating.


----------



## Antman (Jan 6, 2016)

maple1 said:


> I'm kind of wondering about those heat loads.
> 
> 150,000 btu/hr seems like a lot for a place that doesn't get colder than 20f.
> 
> ...


House 1 is 10 years old and friend of the family is one of the bigger insulation guys in the area. He came by last winter on one of those 20F days and looked at the windows and walked through the attic. Said the place was well insulated and stated that the wood windows were very good because he couldn't feed any cold air coming through.

I did the heat loss calculation twice, once using slant fin, and again using the Taco hydronic design software. I input the data from the house plans as accurately as I could and came up with 150MBH using slant fin and I think 135MBH using Taco software. I guess I just used the higher number because it more closely matched the output ratings on the LP furnaces:

BTUH output on 2.5 ton LP furnace with the 14x20 supply plenum listed at 30,000, 80% efficiency
BTUH output on 4 ton LP furnace with the 17x20 supply plenum listed at 48,000, 80% efficiency
BTUH output on 5 ton LP furnace with the 20x20 supply plenum listed at 80,000, 80% efficiency, (i.e. 100,000 BTUH input)

30,000 + 48,000 + 80,000 = 158,000 BTUH output when all furnaces calling for heat

The biggest factor is probably the 10' ceiling downstairs and 9' ceilings upstairs. I am also in the middle of 40 acres up on a hill so winds steal a lot of the heat by (?convection)

This is the little lumberjack and my Chesapeake Bay Retriever winding up a day on the Garn Barn.


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## maple1 (Jan 6, 2016)

Antman said:


> I really appreciate everyone's feedback and support!
> 
> Thank you, thank you, thank you!
> 
> ...


 
I don't know what the implication for 3/4" lines was. But if it was for the underground, I would forget about that - you could never move enough water for your loads.

And sure, going to huge excessive storage like that would extend time between burns. But it would also seriously increase the load on the Garn when it needs charged again, and from what I have read about the Garn, it might not cope very well - needing periods of shut down for cleaning out the ash. If you were looking at needing longer periods of continuous burning (as opposed to batch burning in periods of a load or two), you might be better served by a different boiler of the downdraft variety. But sounds like it's too late for that kind of a major component change.


----------



## jebatty (Jan 6, 2016)

My brain is a bit dense this morning, but I don't see how 3/4" pex @ 4 gal/min will work, and Leon is going to have to explain that with a diagram, math, pump head, circulator specs, etc. for me to see how it could work.


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## maple1 (Jan 6, 2016)

Antman said:


> House 1 is 10 years old and friend of the family is one of the bigger insulation guys in the area. He came by last winter on one of those 20F days and looked at the windows and walked through the attic. Said the place was well insulated and stated that the wood windows were very good because he couldn't feed any cold air coming through.
> 
> I did the heat loss calculation twice, once using slant fin, and again using the Taco hydronic design software. I input the data from the house plans as accurately as I could and came up with 150MBH using slant fin and I think 135MBH using Taco software. I guess I just used the higher number because it more closely matched the output ratings on the LP furnaces:
> 
> ...


 
So House 1 has 3 furnaces? I might think about putting some sort of run-time meters (hour meters?) on them if possible to see how much they are actually running, say during the course of a typical month of winter. 150,000btu/hr is a huge heat load. Not saying it's not right - just seems very big. Haven't seen the house, either, though.


----------



## Antman (Jan 6, 2016)

maple1 said:


> No. Well, sorta. Resistance electric heat uses local utility electric to heat water via elements. As opposed to say a heat pump, which uses utility electric to heat via refrigeration techniques.
> 
> My DHW tank heats my DHW in the summer the same way as my backup electric boiler heats my house when there is no wood fire going on. Only difference is the DHW tank uses one 4500w element at a time, whereas the electric boiler has 4 of them going, as needed.
> 
> You do have more hot water usage than we do. Up until last summer, we had 2 adults & 3 teenagers. No baths but showers every day (usually). But overall, with checking out power bills & heat useage, our space heating demand is about 30x what our DHW demand is, in kwh. Roughly estimating.


So in my case, 150MBH/30 = 5MBH or 5,000 btuh which is consistent with page 7 of the Garn Design Manual for one DHW tank, but I have 3 50gal tanks so maybe I'd fall somewhere between 5,000-15,000 btuh range?


----------



## Antman (Jan 6, 2016)

maple1 said:


> I don't know what the implication for 3/4" lines was. But if it was for the underground, I would forget about that - you could never move enough water for your loads.
> 
> And sure, going to huge excessive storage like that would extend time between burns. But it would also seriously increase the load on the Garn when it needs charged again, and from what I have read about the Garn, it might not cope very well - needing periods of shut down for cleaning out the ash. If you were looking at needing longer periods of continuous burning (as opposed to batch burning in periods of a load or two), you might be better served by a different boiler of the downdraft variety. But sounds like it's too late for that kind of a major component change.


Yes, I actually don't mind firing multiple times per day if required. Just hoping to minimize loading any way possible in case I have to rely on someone else to do it.


----------



## Antman (Jan 6, 2016)

maple1 said:


> So House 1 has 3 furnaces? I might think about putting some sort of run-time meters (hour meters?) on them if possible to see how much they are actually running, say during the course of a typical month of winter. 150,000btu/hr is a huge heat load. Not saying it's not right - just seems very big. Haven't seen the house, either, though.


I posted a pic of the lay of the land. Run time meter is a great idea. Now is a perfect time to do it. Thank you.


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## maple1 (Jan 6, 2016)

Antman said:


> So in my case, 150MBH/30 = 5MBH or 5,000 btuh which is consistent with page 7 of the Garn Design Manual for one DHW tank, but I have 3 50gal tanks so maybe I'd fall somewhere between 5,000-15,000 btuh range?


 
Having that many tanks isn't directly correlated to how much DHW is used. Similar to having 150,000 btuh of furnace capacity might not mean you need that much - how active they actually are for the loads they are meeting is the teller of the tale. Since you are at the right place in the designing stage for it - I would seriously try to accurately monitor how much time all of your heating devices actually spend heating.


----------



## Antman (Jan 6, 2016)

maple1 said:


> Having that many tanks isn't directly correlated to how much DHW is used. Similar to having 150,000 btuh of furnace capacity might not mean you need that much - how active they actually are for the loads they are meeting is the teller of the tale. Since you are at the right place in the designing stage for it - I would seriously try to accurately monitor how much time all of your heating devices actually spend heating.


understood. I'm all for knowing if maybe I don't need those 1-1/2" logstor dualpex after all. do you have a website for the device, if not I'll call my brother in law who is in HVAC


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## leon (Jan 6, 2016)

Antman said:


> I really appreciate everyone's feedback and support!
> 
> Thank you, thank you, thank you!
> 
> ...


=================================================================================================


Each and every gallon of hot water has only so many BTuH it can deliver.

Based on a 20 degree temperature drop one gallon per minute of flow will transport 10,000 BTuH

SO 4 GPM will deliver 40,000 BTuH to your heating loads Per Loop

The suplus tank car could go in your carriage shed next to the Garn boiler you have to plan on having 38 feet to park it and have a pair of concrete hemispere supports cast in the floor to support it.

BUT saying that there is no reason you could not use good hardwood cribbing 12 by 12 by 12 to create a long enough crib to support the tank car body minus the trucks and axles. if you bought it with the trucks and axles it would double the price and you dont want that!  

Hiring a house mover to set that up will save you time and money aggravation as they have all the goodies-NO a large tractor will not do it!!

You may need a separate slab if you have a shallow thickness of concrete in the floor- I have to go now-many errands for boiler install. BUT the hardwood cribbing may be all you need for this if you pursue that route.

You have to think of the tank or tanks as 10,000 gallons of thermal mass and only thermal mass. Your going to have that amount of gallons to make hot water and hold hot water for you.

The firing rate of your garn is going to depend on your heating load after you have the water heated to the temperature you want.

Your going to have to empty the ashes to keep up a hot fire and keep it burning hot and then you may end up increasing the water high limit temperature even more to keep up.

So much of this is going to depend on your first season of use to create the right amount of hot water  for your heating loads and having system bypass loops are going to save you energy as a portion of the water will return to the garn boiler hotter than the low limit temperature and raise the boilers water temperature and hopefully reduce cycling.

I would want to install circuit setters in each heating loop to return at least one gallon per minute back to the return loop uphill to the garn boiler to start with and you can always open them up for full flow to the heating load if three gallons a minute of hot water is not enough.

Ideally you want the smallest water to air heat exchangers in your ducts as they are nothing but energy hogs and will strip the water of its heat value quickly.


----------



## Antman (Jan 6, 2016)

leon said:


> =================================================================================================
> 
> 
> Each and every gallon of hot water has only so many BTuH it can deliver.
> ...


The slab is 40'x20' with 10' ceiling so it would probably be too tight to maneuver that much weight but another slab could conceivably go adjacent to the barn under a deck which is planned for after both houses are completed. Very interested to see how the 3/4" design could work...


----------



## leon (Jan 6, 2016)

SO if you are pushing 4 gallons per minute through the 3/4 pex you are delivering 240 gallons per hour at 40,000 BTuH=2,400,000 per day per heating load making 4,800,000 in 24 hours theoretically.

The 4 GPM figure I used is for a "no water noise" in baseboard loops figure from the baseboard folks.

It is theoretically possible that the simple act of thermosyphoning  may be enough to do this as you have 2,000 gallons of hot water in the garn and once it starts moving down hill with venting the line properly at the heating load using a boiler drain on the return line with a garden hose draped into a laundry sink you will not get all the air out on the first firing.  

So a gallon of water weighs 8.34 pounds times 2,000 pounds is 16,680 pounds= (8 tons+680 pounds)

SO a single loop will have that water weight wanting to take advantage of the situation by simple gravity because water is lazy just like electricity it will go just about anywhere.


You seriously need to talk to a mechanical engineer about this and pay for an hour of his time and then you will have all your answers as a thermosyphon could work- remember water is pumped up hill and flows down hill naturally- our city water system has a very tall gravity drop and has worked this way for a hundred years now and it works very well.

Your looking at physics and head pressure at its finest hour with 2,000 gallons of water(8 plus tons) sitting above your heating load.

You have 2K (8 tons) of hot water at an altitude of 30 feet above the point of use
you have the $15 3/4" dual pex laying in the ground, you have 8 tons of water weight wanting to blow outof the garn tank creating pressure against the tank walls with one or two outlets not including the by boiler pass loop if you have one-you should just to make life easier and raduce cycling as your heating load(s) will stop calling for heat at one time or another. 

Water pressure at sea level is 14.21 PSI depending- SO you have all that hot water with all its heat wanting to escape and waddle off someplace other than where it is.

So you have 3/4 Pex that can push more than 4 gallons per minute(more like 50) without batting an eye and the pressure is only regulated with the pex pipes inside diameter, the Pex pipe length, the back pressure created by the resistance in the pipe and the heating loops, and the return piping to the tank.

I want you to think of a marble as Dan would say, If it came to a Tee where would it go? How fast would it get there? How does gravity work in this case its all down hill like a bad day.

Hooking up one heating load and then a second in the same loop does a couple of things for you.

The first heating load strips heat out of the water and leaves the neighborhood for parts unknown(not really) the cooler water wanders over to the next house and the heating load in that house strips even more heat out of the water than the water waddles out for parts known only to you and the dual 3/4 pex back up hill to the garn barn and Viola the water is pushed back into the garn to be heated once more for the job of transferring 10,000 BTUh per gallon,

The gallon of water waddles down hill at a rate of 4 gallons per minute with its brothers and sisters and then creeps up hill to the garn at 240 gallons per hour 5,760 gallons per day in one loop that runs from one house to the next and back to the garn barn to be reheated so it can deliver 10,000 BTuH and the work continues

SO you have 8 plus tons of water pushing 33 pounds of water through the single loop(if its regulated) and its wanting to get out of the way for the rest of the water family to get through there.

I really want you to talk to a mechanical engineer as yoiu can take advantage of this with a really small circulator at the garn and the mechanical advantage you will have is in the 8 tons of hot water just sitting there.

Be the marble.

Do not forget that 1 GPM is 60 GPH and 1,440 gallons per day in the scheme of things and if you heat the garn to
180 high limit, gravity and a thermosyphon and the 8 tons of water weight in that tank are your friend.
The water is pushing from the garn to the first house then to the second house and then back to the garn. 


Talk to a mechanical engineer and pay him for an hour of his time explaining your system, the altitude of the garn above the heating load and how you are examining pipe size for pex etc., and then go from there and you should have an answer to your issues. and you just may be able to thermosyphon to deliver heat to your heating loads.

Just think of how lazy the water family will be if 8K of additional hot water(33 tons+-) is pushing its family down hill in that 3/4 pex and wanting to get there, wherever there is.

Think like the marble, think of the garn as a simple platform scale with a pail of marbles that will slide down a pipe, think of a pipe loop as a horse shoe and the marble has to follow the inside loop of the horse shoe if you roll it in the inside and its slick enough the marbles will roll right up and jump back in the bucket.  

Its not the most eloquent expalanation but I am tired so....................


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## maple1 (Jan 6, 2016)

Leon, did you calc head loss for all that underground 3/4" pipe?

It won't work.


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## leon (Jan 6, 2016)

Hey maple1,

I just crawled back inside from town, still waiting on plumbers.
I was thinking of 160-180 degree water high limit water temps  

With the $15.00 Pex losing a degree for every 100 feet I did not think it
would amount to much- But I did not include the two heat loads stripping
the heat from the water.


----------



## maple1 (Jan 6, 2016)

I was talking more of the issue of just getting that much flow through that much 3/4" pipe over that much distance with a reasonably sized pump. All in all, this is a rather challenging project, but should be do-able with a proper amount of pre-thinking.

Had one more thought on the run-time monitoring related talk above. You might also get a verification or rough 'second opinion' on the heat load if you have a decent history of past fuel useage over the course of a winter. Or winters. Not sure how old they are & how long you've been there though.


----------



## leon (Jan 6, 2016)

Hello maple1,

If I wanted to use the hydraulic pump as an example you 
could pump fifty gallons per minute through a 3/4 inch hydraulic 
hose it at 100 PSI. Hydraulic pumps are tested at 100 PSI and 
1,200 RPM to get a base line flow rate at that pressure and RPM.

small sump pumps and drainage pumps operate at high speeds with no little to no resistance 
to the discharge end of the hose/pipe 

It would make a huge amount of noise but I digress.

I suppose you could use a centrifugal pump to push the water back up hill in an 
insulated utility room in the home that is heated last and then the water could be 
pushed uphill as is done in skyscrapers using a check valve cartridge like the ones in the 
B+G NRF pumps I have the NRF 25 set at the number one speed for the heating loop 
and the temperature balancing pump and they both pump about 17 G.P.M. with 3/4 piping 
with little head loss as the baseboard is on one level with no restrictions and they are extremely 
quiet as all the air is gone in my boilers- that will change tomorrow when they are removed 
if the plumber shows up and the dual fuel coal stoker is installed but the air will not be 
there for long once the loops are vented and the boiler drain on the module is shut off and what 
little air is remaining will be what is in the boiler when the pump is running and the air vent line is 
opened to the steel expansion tank.

I would be willing to say the 2,000 gallons he has in the Garn is a big start toward gravity circulation 
for his heating needs with 3/4 inch pipe creating the head pressure for a thermosiphon condition  
to occur almost naturally using simple valves to control it. 
=======================================================================================
I do not know if  using the Garn as nurse tank to either of the homes could be an option with a smaller tank connected 
to  the heating load in each home But the thermo-siphon method for heating is proven and simpler to plumb up and the 
Garn barn is on the uphill side where it will be making all that hot water.

A float tank fed from the Garn may be all he needs to create the siphon and feed the single or double loop of 3/4 dual pex.  
It would be easy enough to plumb in a steel stock tank and cover it with marine plywood and install a float valve and 
let it flow downhill- car washes do this to have hot water on standby taking it from  flash boiler and refilling the tank as 
needed with hot water made by the flash boiler.

I hope he talks to a mechanical engineer about this issue  and not an HVAC engineer as he has height and the rise and 
run to take advantage of the 8 plus tons of water he is going to have in his Garn boiler and even more water if he buys 
a surplus 8,000 gallon insulated tank car.


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## Antman (Jan 7, 2016)

leon said:


> SO if you are pushing 4 gallons per minute through the 3/4 pex you are delivering 240 gallons per hour at 40,000 BTuH=2,400,000 per day per heating load making 4,800,000 in 24 hours theoretically.
> 
> The 4 GPM figure I used is for a "no water noise" in baseboard loops figure from the baseboard folks.
> 
> ...



I will try to locate a mechanical engineer to discuss thermosyphoning in this context in more detail. I'd like to clarify that the Garn Barn (GB) slab is only 3' above house 1 and house 2 grades, not 30'. I was hoping 30' was a typo in your analysis, but please forgive me if that wasn't clear. I've attached a diagram attempting to illustrate this further. I tried to draw to scale as much as possible. I can draw the houses larger if my writing is too small to be clear. Also, the highest point in the system for house 1 is 5' above the floor of the attic that is above the 2nd floor (23' above the level of the Garn Barn slab) where the 4 and 5 ton LP furnace supply plenums (17x20 and 20x20 WTAHX) are 5' above that floor.

Don't get me wrong, I'd absolutely LOVE to run the hot water from GB to house 1, and back past the GB all the way to house 2 prior to returning to the GB because house 2 only needs ~110F for radiant floor heating. This is how I originally though the system could be designed. I guess the downside to putting both homes in series, aside from the head loss issue, is that if one house is down, both houses likely would be down. Please correct me if I'm wrong, but I would think the most likely reason for the system to go down, assuming a leak-proof, pressure-checked, installation, would be a bad pump. That solution could be as simple as keeping 2 of each circulator/zone valve, one for backup if the corresponding operating unit fails.

Like maple1, I just can't see how to overcome this kind of head loss using small circulators and 1-1/4" or 1-1/2" logstor, much less 3/4" logstor. That's why I thought I'd need to break the install up into house 1 this year and house 2 next year. I guess I could possibly use larger circulators, but I was trying to use small ones if possible because I'm interested in minimizing power consumption in the event that I run the whole thing one day on solar.

As I understand, a reasonable estimate of head loss is:

Head loss = length of the longest loop * 1.5 (to account for resistance of fittings, HX's, bends in the pex, etc.) * 0.04 (all water with no glycol)

Head loss for house 1
560' * 1.5 * 0.04 = *34 feet of head* (barn to highest and furthest points in house 1, and back to barn),
where 560' = [230' (GB to house 1) + 50' (distance from buried dualpex up into the attic and all the way over to the 17x20 and 20x20 WTAHX)]*2

Head loss for house 2
900' * 1.5 * 0.04 = *54 feet of head* (GB to radiant supply manifolds, through any 300' loop, back to return manifold, and back to GB)

That is a rather large head loss for either circuit alone, much less combined:
34 + 54 = *88 feet of head*

BTW, these head loss numbers seem to correlate with the Garn Design Manual. Referring to pages 13 and 14, a system designed with 20F dT's could flow hot water through 0.678" ID barrier pex (i.e. logstor 3/4") at 3GPM and 4.5GPM and deliver 30MBH (4 feet of head per 100') and 45MBH (6 feet of head per 100'), respectively.

At the 3GPM flow rate, a perfectly straight 560' pex pipe would see:

560' * (4FOH / 100') = 22.4 FOH

Similarly:

560' * (6FOH / 100') = 33.6 FOH
900' * (4FOH / 100') = 36 FOH
900' * (6FOH / 100') = 54 FOH

Add 50% of these values to themselves (the 1.5 figure in the calculations above) and you're in the same ballpark

As a side note, another reason I like your system description is that I don't plan to run glycol and the bypass allows for continual flow which would minimize any risk of lines freezing as long as there is no power outage. My planned LP backup generator for house 1 could provide that assurance because I'm running a 200 amp service from house 1 to the GB. The electrician can put all Garn and house 1 circulators, zone valves, etc. on that generator. House 2 already has a gasoline backup generator to do the same there.

Can you please provide some diagrams illustrating how a 3/4" system could be configured to do this?


----------



## Antman (Jan 7, 2016)

maple1 said:


> I was talking more of the issue of just getting that much flow through that much 3/4" pipe over that much distance with a reasonably sized pump. All in all, this is a rather challenging project, but should be do-able with a proper amount of pre-thinking.
> 
> Had one more thought on the run-time monitoring related talk above. You might also get a verification or rough 'second opinion' on the heat load if you have a decent history of past fuel useage over the course of a winter. Or winters. Not sure how old they are & how long you've been there though.


We've been here 4 years so I have a handle on propane usage. For house 1, the furnaces are 2005 goodman and we burn ~2000 gallons of LP  per season (the 3 furnaces, 3 DHW, and stovetop, and very rarely the LP fireplace - no chimney). We have an LP pool heater but elected not to repair it as it wasn't working when we moved in. The hot tub and all other appliances are currently electric. House 2 burns 400 gallons of LP per season (single LP furnace), all other appliance are electric. I'll have to get in the attic and check how old that furnace is, but eventually it will only be for backup heat (no plan for WTAHX as it will have radiant floor)


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## maple1 (Jan 7, 2016)

Antman said:


> We've been here 4 years so I have a handle on propane usage. For house 1, the furnaces are 2005 goodman and we burn ~2000 gallons of LP  per season (the 3 furnaces, 3 DHW, and stovetop, and very rarely the LP fireplace - no chimney). We have an LP pool heater but elected not to repair it as it wasn't working when we moved in. The hot tub and all other appliances are currently electric. House 2 burns 400 gallons of LP per season (single LP furnace), all other appliance are electric. I'll have to get in the attic and check how old that furnace is, but eventually it will only be for backup heat (no plan for WTAHX as it will have radiant floor)


 
I just did some quick Googling, and made a couple of assumptions.

Found a figure of 91,333 btu/gal for LP.

Taking the 2000 gallon LP figure for house 1, and guessing that was for 6 months, I came up with around 42,000 btu/hr. of average fuel use. Throwing another assumption in of 80% efficiency, means the 42,000 btu/hr of fuel used is about 35,000 btu/hr delivered to the house.

You would no doubt need more than an average, during the coldest months. I'm not sure how much more though, or if there is a rough quick factor some use for an off the cuff calc. Heat loss calc should turn it up though. But I wasn't expecting to see the average be 25% of the heat loss calc - but maybe it would be? I haven't done this much.

Playing with numbers is fun, sometimes. Sometimes it leads to head scratching & hair loss. Would like to see more input on things & more number playing from others. Also some run-time measuring during the coldest months should bring a clearer picture.

(I might have also done something wrong....)


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## Antman (Jan 7, 2016)

Latest iteration for clarification on a way to put both houses in a series with 3/4" ID pex.  I cannot visualize it but I am keeping my mind open to what Leon and Dan can share.


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## leon (Jan 7, 2016)

Antman said:


> I will try to locate a mechanical engineer to discuss thermosyphoning in this context in more detail. I'd like to clarify that the Garn Barn (GB) slab is only 3' above house 1 and house 2 grades, not 30'. I was hoping 30' was a typo in your analysis, but please forgive me if that wasn't clear. I've attached a diagram attempting to illustrate this further. I tried to draw to scale as much as possible. I can draw the houses larger if my writing is too small to be clear. Also, the highest point in the system for house 1 is 5' above the floor of the attic that is above the 2nd floor (23' above the level of the Garn Barn slab) where the 4 and 5 ton LP furnace supply plenums (17x20 and 20x20 WTAHX) are 5' above that floor.
> 
> Don't get me wrong, I'd absolutely LOVE to run the hot water from GB to house 1, and back past the GB all the way to house 2 prior to returning to the GB because house 2 only needs ~110F for radiant floor heating. This is how I originally though the system could be designed. I guess the downside to putting both homes in series, aside from the head loss issue, is that if one house is down, both houses likely would be down. Please correct me if I'm wrong, but I would think the most likely reason for the system to go down, assuming a leak-proof, pressure-checked, installation, would be a bad pump. That solution could be as simple as keeping 2 of each circulator/zone valve, one for backup if the corresponding operating unit fails.
> 
> ...







Hello and good morning antman,  maple1, Still to early and waiting on plumber 

Your current illustration is perfect antman. That helps me, because a circulator is just like a trash water pump, run, run, run, push water, push water, push water, push water to a discharge point at the end of a hose.

A circulator with a check valve may be all that is necessary. 

They use them in three story building for hot water heat and cooling towers with no issues
in my case I am circulating through 250 feet of base board in a poorly insulated house and I do not have a check valve in either of my circulator's.

Find a local mechanical engineer. The national mechanical engineering society can help you find someone-can remember the groups name right now but a nearby university with an engineering curriculum can direct you to one I am sure

I have to go.


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## maple1 (Jan 7, 2016)

I'm quite sure I wouldn't do series, and I would definitely not use 3/4" pipe underground.

For one thing - in the last diagram, the flow to house 2 is limited to what is flowing through the loads in house 1.

Although, I don't think we've seen the exact horizontal relationship between all three points of interest - barn, and two houses. One diagram showed the barn being between the two houses, houses being 230' & 300' in opposite directions (post 48 after looking back). Whereas the one in post 51 notes a 900' loop & 560' loop. I assume there is a triangle of sorts connecting the 3? Depending on that geometry, primary/secondary may even be a consideration.


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## Karl_northwind (Jan 7, 2016)

skimmed the thread,  didn't read it all.  are the 2 houses in line, IE would you later be running house 2 off the same lines that go to house 1?   your heat source is bought, so unless you want to add a second wood boiler, we have to work with what we have.
figuring the 150kbtu/h you calculated, 600' of 1.5" pex round trip at 15 GPM will require about 27' head loss (and 14 gpm=23').  a taco 2400-20 will do that, although I'd consider upping that one size to a 2400-45 if it's going to feed both houses.

I just did my first set of foamed in place lines, (copper)  and the price was really reasonable compared to logstor or anything else.  the 1.5" uponor with EP fittings would be fine.  2" might be even better, at a couple bucks a foot higher price.  the foam ran about $5 per foot.  plus $8? per foot for 1.5" pex ($4x2) for $13 a foot you have durn good insulation, durn good flow.

keep the circulator near the boiler to remove issues with the NPSH on that circulator, and that will help too.
the 2000 is a little small for that load, but most of the year it'll handle all the load, and part of the year it'll handle most of the load. 
karl

also, zoning with small circulators in the basement to deliver to the house air coils will help them self purge should a little air get in them.


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## leon (Jan 7, 2016)

Antman said:


> I will try to locate a mechanical engineer to discuss thermosyphoning in this context in more detail. I'd like to clarify that the Garn Barn (GB) slab is only 3' above house 1 and house 2 grades, not 30'. I was hoping 30' was a typo in your analysis, but please forgive me if that wasn't clear. I've attached a diagram attempting to illustrate this further. I tried to draw to scale as much as possible. I can draw the houses larger if my writing is too small to be clear. Also, the highest point in the system for house 1 is 5' above the floor of the attic that is above the 2nd floor (23' above the level of the Garn Barn slab) where the 4 and 5 ton LP furnace supply plenums (17x20 and 20x20 WTAHX) are 5' above that floor.
> 
> Don't get me wrong, I'd absolutely LOVE to run the hot water from GB to house 1, and back past the GB all the way to house 2 prior to returning to the GB because house 2 only needs ~110F for radiant floor heating. This is how I originally though the system could be designed. I guess the downside to putting both homes in series, aside from the head loss issue, is that if one house is down, both houses likely would be down. Please correct me if I'm wrong, but I would think the most likely reason for the system to go down, assuming a leak-proof, pressure-checked, installation, would be a bad pump. That solution could be as simple as keeping 2 of each circulator/zone valve, one for backup if the corresponding operating unit fails.
> 
> ...







Hello and good morning antman,  maple1, Still to early and waiting on plumber 

Your current illustration is perfect antman. That helps me, because a circulator is just like a trash water pump, run, run, run, push water, push water, push water, push water to a discharge point at the end of a hose.

A circulator with a check valve may be all that is necessary. 

They use them in three story building for hot water heat and cooling towers with no issues
in my case I am circulating through 250 feet of base board in a poorly insulated house and I do not have a check valve in either of my circulator's.

Find a local mechanical engineer. The national mechanical engineering society can help you find someone-can remember the groups name right now but a nearby university with an engineering curriculum can direct you to one I am sure

I have to go.


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## Antman (Jan 7, 2016)

maple1 said:


> I'm quite sure I wouldn't do series, and I would definitely not use 3/4" pipe underground.
> 
> For one thing - in the last diagram, the flow to house 2 is limited to what is flowing through the loads in house 1.
> 
> Although, I don't think we've seen the exact horizontal relationship between all three points of interest - barn, and two houses. One diagram showed the barn being between the two houses, houses being 230' & 300' in opposite directions (post 48 after looking back). Whereas the one in post 51 notes a 900' loop & 560' loop. I assume there is a triangle of sorts connecting the 3? Depending on that geometry, primary/secondary may even be a consideration.



The knockout for underground lines coming into the back of the GB is in right on a straight line between the two points of entry into both homes. From that point to house 1 is 230' and to house 2 is 300'. The longest loop happens to be highest point of the system for house 1. For house 2, it happens to be through any one of the 7 radiant floor loops, which I understand for radiant floor shouldn't be more than 300'. I've attached an illustration.

So, to get out of the ground, up into the attic and over to the highest point in the system for house 1, there is an additional 50'. That means 230' + 50' to the furthest load or 280' is half the loop. To get from there back to the GB requires an additional 280' making the longest loop 560' which is the length I used to estimate head loss for house 1:

560' * 1.5 * 0.04 = *34 feet of head*

As for house 2, it takes 300' to get into the house and to the supply manifold, 300' through the longest run of radiant floor and back to the return manifold, then another 300' back to the GB which totals 900' which I used to estimate head loss for house 2:

900' * 1.5 * 0.04 = *54 feet of head*


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## leon (Jan 7, 2016)

With 54 feet of head is about three and a half stories with tall ceilings in comparison.

the  B+G NRF36 without a check valve is in that range using speed three and 
reaching 34-35 feet of head pressure at 37 gallons per minute+-.

Measure three times, take aspirin or Tylenol or Advil, measure again, then sit down and 
look at the big picture as to where you can park a circulator.

Then you see where the back pressure of the 2,000 gallons of heated water in the Garn boiler 
will only be a help to you as the circulator will be blessed with a "flooded suction" condition 
wherein the water is always there no matter the pump speed.

As long as you have "flooded suction" at the circulator inlet your circulator will run cool 
and quiet with no air bubbles. 
=========================================================================
The question is more of "do I want a one inch feeder pex from the Garn to the 3/4 inlet of the
NRF-36 which would be a possibility as flooded suction is always a circulator's best 
friend. 
==========================================================================
The same applies to a less costly gear pump for a commercial log splitter. as flooded suction 
always, always, always helps in keeping a gear pump wet and removing air bubbles.  

Lots of ways to do this "BUT" all it is is a simple water pumping problem with a "dumb" low pressure circulator
operating at 1,750 RPM with restrictions from air handlers and radiant in floor heat.

Once you start pushing even heat through the system using speed three you may be able to slow the pump 
down after the air bubbles are out and save on heat losses from the Garn with or without a system bypass loop.

The circulator will not overheat from lack of flow as the suction port is always flooded and cooling the impeller 
housing and impeller.

Once the air is gone and there is little to no turbulence except for any micro bubbles at the initial start up that 
can be dealt with a drop or two of dawn dish soap in the pump inlet.  

"Pumping", "Circulator", "water flowing through  "X" sized pipe" problems require a mechanical engineers insight for this 
situation as you have a potential racetrack for water flow there to take advantage of.

You have a cooling tower with two chilling loads if you look at as a cooling problem, that is the only difference in my 
thought anyway.


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## maple1 (Jan 7, 2016)

leon said:


> the  B+G NRF36 without a check valve is in that range using speed three and
> reaching 34-35 feet of head pressure at 37 gallons per minute+-.


 
A pump curve chart for a B&G NRF36 shows that at 34 feet of head, the pump will flow exactly ZERO gpm using speed three. If you could knock it down to 30 feet, you might get 5 gpm. You need ZERO head to get 37 gpm.

There may be some useful info in your posts, but there is also some misleading & confusing stuff.


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## leon (Jan 7, 2016)

I am sorry if I have confused the issue.

The pump information sheet I have came with the NRF 25 pump I bought listing the four pump models and the specs for them 

On the cover sheet/first page they list the operational limits for these pumps as 150PSI with a maximum operating temperature 
of 225 degrees. The electrical ratings are for 115 volts and 230 volts 


The left side of the graph Lists (kpa) (M) then (FT).

The lower portion of the graph lists GPM from 0-60 GPM
then the metric conversion scale is 0 to 13 (cubic meters/hr)
then below that it lists 0 to 3 (l/s) liters per second


For the NRF 36
speed three peaks at 33 FT+- and on the lower graph the flow peaks near 38 G.P.M. +-
speed two peaks at just under 30 FT and on the lower graph the flow peaks just at 32 G.P.M.+-  
speed one peaks at a hair over 25 FT and on the lower graph flow peaks just over 25 G.P.M.+-


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## maple1 (Jan 7, 2016)

Right - so looking at the curve itself, and seeing when the vertical or left side of the graph is at 33ft, if you try to follow that 33ft level over to the right you are immediately at the pump curve line, so then if go vertically down from there to the bottom scale you're at zero on the horizontal flow numbers. (From memory, give or take - don't have it in front of me right now). Meaning at 33ft of head, the pump doesn't pump anything. Or, another example from memory, if you start at the 30ft head on the vertical axis on the left side, and go horizontal to the right until you hit the curve, then go vertically down to hit the horizontal flow axis, you come to around 5 gpm. Meaning at 30 ft of head, it flows 5 gpm.

Just trying to alleviate some possible confusion.

And I am, as always, also open to the same alleviation if I get mistaken about something - par for the forum & what makes it a good resource.


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## jebatty (Jan 8, 2016)

A design such as yours, Antman, I find to be very challenging. I haven't added much input because I'm not sure I have the expertise to lead you to a satisfactory result. From my experience I do know that undersized pipe and long distances are major fundamental contributors to disappointment in or failure of installations.


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## Antman (Jan 8, 2016)

jebatty said:


> A design such as yours, Antman, I find to be very challenging. I haven't added much input because I'm not sure I have the expertise to lead you to a satisfactory result. From my experience I do know that undersized pipe and long distances are major fundamental contributors to disappointment in or failure of installations.


Yes, am putting a pressurized design together using 1-1/2" logstor for the primary loop as the head pressure appears to be half that of the 1-1/4". The Taco 2400 circs should be able to handle this high head situation presented by the long underground run. The head in the secondary loops should be able to be handled using circulators for those zones.


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## maple1 (Jan 8, 2016)

jebatty said:


> A design such as yours, Antman, I find to be very challenging. I haven't added much input because I'm not sure I have the expertise to lead you to a satisfactory result. From my experience I do know that undersized pipe and long distances are major fundamental contributors to disappointment in or failure of installations.


 
I was thinking this as well - oddly enough, when laying in bed this morning while only half awake. Funny how & when the mind works.

There are quite a few challenges here. Two long underground loops. An unpressurized boiler. Several WAHXs in the furthest reaches of the system, which typically require the hottest supply water. More heat exchangers at the boiler to go from unpressurized to pressurized, and every time you go through a HX you usually lose some off your top end temps. A boiler design that lends itself very well to low temp emitters but is I think somewhat limited when it needs to supply consistent high temp water (from reading), as well as maybe also not doing the stratification game as well as others, as well as maybe not as fast to supply its hottest water in the earlier stages of burn.

I think you would be on the right track with the last post. Keep the two main undergound runs as short as possible with fat pipe. Just get them in the house to a manifold as soon as possible (manifolds just inside the house). Then have more pumps inside, one for each load. Then on call for heat, you would have the main undergound pump doing its thing while also getting assist from the load pump(s). If you can find pumps for each that sound like they might be bigger than needed, but are multi-speed, you could have some tunability. Big pumps are expensive though - both to buy, and to keep running (power consumption). That's where the investment in bigger underground will pay back. I was thinking primary/secondary setup might work - primary underground loops to get to the houses, then secondary flows through close Ts for the loads inside. But the secondary close T flows would not provide any assist for the main loops, whereas a manifold setup should. And with 3 load HXs , each successive one would see decreasing supply temps if a close T setup were used.

Has Garn been spoken with re. the issue of using HXs to go from unpressurized to pressurized? And the elevations involved? I would seek their input before plunging fully in. Just wondering about the returns of doing that vs. the bit of loss of top end temps. That's one aspect of the design there hasn't been a whole lot of input on. Stepping back a bit, I am quite sure that there are OWB owners that have somewhat the same situation - an open boiler with a long undergound run. I am sure this could be done, just not sure about the best way to do it - very big pumps are also common in some OWB setups.


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## Karl_northwind (Jan 8, 2016)

If you do the Logstor 1.5" you have a better situation than 1.5" Uponor.  1.5" logstor has an ID of 1.6" ID, better than the number I was using.  if you do to and from the GB with 1.5" to house #1, you have a head loss of 11' at 600LF of pipe and 15 GPM.
that's way better. 
house 2 at 600 feet would need lower flow rate most of the time, as the floor loops can mix the temp down to 100F probably. 
you won't use one pump to pump the entire 900 feet with house 2, you'd use one pump to move the 600' of 1.5" pipe, and do as maple suggested, connect a pair of closely spaced tees with another circulator pushing thru the floor loops when there is a heat call for any particular zone.   or you use a flat plate heat exchanger in the building (could be either the GB or house 1) and run the heating loops pressurized. (as a contractor this is what I would do, because if there are air problems in the floor loops, I have to go back and fix it and that costs the price of a heat exchanger the first time I have to go back.)

on a separate topic, while you're waiting for Dan's books (and they're worth the wait, if nothing else, for the pickle story) read Caleffi's Idronics series.  google them (they're free PDFs) and read them in order, and you'll have a really decent handle on what is going on in hydronics. the ones that deal with topics you don't particularly care about, just skim and look at the nice pictures.

cheers,
karl


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## Karl_northwind (Jan 8, 2016)

that would put you in the range of a taco 0014, using 174 watts/hr versus 228 watts/hr for a 2400-20:  that would save you about 1.5KWH/day, or 15 cents a day, and $55 per year.  for the next 20 or 30 years, that adds up. you might find that you'll save $ by going with the smaller PEX, and running a high efficiency ECM circulator from wilo or grundfos.  you'll have to do the math on that.


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## Antman (Jan 8, 2016)

maple1 said:


> Just get them in the house to a manifold as soon as possible (manifolds just inside the house).


I originally had planned to do that until I couldn't find high-flow manifold units with larger than 3/4" outlets. I haven't put that much thought in how to build one yet, because, up until recently, I have been trying to build an open system. It seems that pressurizing may solve several problems for me:

1. oxidation (able to use cast iron pumps)
2. raising water to the highest point of the system where the loads are the greatest
3. less pressure drop across the circulators (less energy required to move water)

Can black pipe tees and nipples be used to build that manifold? I guess I may as well go ahead sweat a copper manifold as I'll already need to be doing that for the WTAHX? Are there any other options for manifolds?


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## Antman (Jan 8, 2016)

maple1 said:


> But the secondary close T flows would not provide any assist for the main loops, whereas a manifold setup should.


If my secondary circs can better assist the primary circ, I guess a manifold serves me a lot more than the easier to build close tees. In building the manifold, is there anything in particular that lends itself to assisting the primary circ?


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## Karl_northwind (Jan 8, 2016)

Antman said:


> If my secondary circs can better assist the primary circ, I guess a manifold serves me a lot more than the easier to build close tees. In building the manifold, is there anything in particular that lends itself to assisting the primary circ?


you can certainly build it out of copper or black iron.  you'll find out that black iron fittings are way cheaper than copper in the larger sizes. 
if you put a swing check valve between the two secondary tees, you will get a little ghost flow, so use a flow check in the pump, but the secondary pump will assist the primary pump move the fluid along, but ONLY if the secondary flow is higher than the primary loop's flow.


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## Antman (Jan 8, 2016)

Karl_northwind said:


> or you use a flat plate heat exchanger in the building (could be either the GB or house 1) and run the heating loops pressurized. (as a contractor this is what I would do, because if there are air problems in the floor loops, I have to go back and fix it and that costs the price of a heat exchanger the first time I have to go back.)


thanks for following my thread, I appreciate your input. I think I'll put the exchangers in the GB so I can use a smaller, less-expensive circ on the open side (the Garn side) which will need to be stainless steel


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## Antman (Jan 8, 2016)

Karl_northwind said:


> you might find that you'll save $ by going with the smaller PEX, and running a high efficiency ECM circulator from wilo or grundfos.  you'll have to do the math on that.


when you say smaller PEX, I'm assuming you mean for the secondary? I was planning on using a Taco bumble bee in set point mode with temperature sensor in the supply duct after forced air goes through WTAHX


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## Antman (Jan 8, 2016)

So house 1 is getting 1-1/2 logstor but I still need to determine logstor size for house 2. I'll get around to running the headloss after kids go to bed but I'm hoping 1" logstor gets it done


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## Antman (Jan 10, 2016)

Antman said:


> So house 1 is getting 1-1/2 logstor but I still need to determine logstor size for house 2. I'll get around to running the headloss after kids go to bed but I'm hoping 1" logstor gets it done


Read Dan's book pumping away and tried to further refine the schematic. Is there any reason why house 1 couldn't be pressurized and house 2 left unpressurized?


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## leon (Jan 10, 2016)

Good morning antman,

You could do that provided you isolate the flow completely using a shut off valve and
pressure regulator to add water "IF" and only if needed and using the heat exchanger and use
a 30 gallon steel compression tank for more water in the system.
(the only time you add water is if you have a LEAK.

I like the steel compression tanks simply because there is nothing to go wrong with
them nor the worry about the bladder losing pressure through osmosis over time.
A thirty gallon compression tank would be more than adequate for this and makes
the secondary boilers job easier and less taxing on the system 


Right now with my system is at 12 PSI using the 15 gallon steel compression tank
and there is no air scoop large piping runs nor crawling around bleeding radiators.

As long as each and every loop has a boiler drain to fill the loop and a second
boiler drain to vent the water your going to be fine.

As I said I would chat with a mechanical engineer pay for an hour of his or her time and
if the same engineer is a "HVAC qualified" all the better as all your wanting to do is pipe water
from two heating loads and back to a common storage tank using a heat exchanger in one loop
and an open system in the other loop "in this scenario.
================================================================================
Just so you know and understand this:

I want you to think about this please; multistory hotels pump hot water for the guests use from the
basement/sub basement of the hotels in a common feeder pipe with a return loop to the basement
and the hot water that is not used is returned in the same loop to the basement into a
common hot water storage tank to be reheated.
================================================================================

1. your dealing with head pressure and not that much head pressure.

2. dumb pumps either single speed or three speed are "simpler" and easier to work with.

3. flooded suction for circulator's always, always always lets them run cooler and more efficiently,
    but putting the circulator in the return side will create issues with turbulence and air bubbles in a 
    closed system, but put together properly paying attention to the circulators location in regard to 
    the point of no pressure change causes less problems as Dan has illustrated in his books.

a. a steel expansion tank above the boiler keeps two thirds of the tanks low pressure water volume
always flooding the boilers steam jacket and pushing water to the circulator.   

4. check valves work to do one job and one job only, they keep flow moving in one direction. 

5. simple one zone controls are what they are "SIMPLE". 

6. steel expansion tanks have no moving parts, no air scoop, no automatic air vents in the top of the air scoop,  no Schraeder Air Valves.

7. bladder expansion tanks have a "bladder sheet" that is sandwiched in between the upper and
    lower parts of the bladder tank that flexs in relation to pressure and temperature.

Please keep us updated and let us know if you chatted with a Mechanical Engineer and what their thoughts and recommendations are.  


I want you to succeed.


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## heaterman (Jan 12, 2016)

I'll just chime in and say that when it comes to pumping power required in a main circulating loop, there is no substitute for large bore pipe and tube.
The "entry fee" is higher initially but the dividend pays back forever.

The true system requirements will depend on the heat emitters more than anything else. (Think large and low temp with corresponding wide T.) 
10GPM @ a 20* drop = about 100,000btu
5 GPM @ a 40* drop = the same.
Radiant floors, big radiators, oversized water x air heat exchangers, etc. These all allow less GPM to do the same "work".


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## Antman (Jan 13, 2016)

heaterman said:


> I'll just chime in and say that when it comes to pumping power required in a main circulating loop, there is no substitute for large bore pipe and tube.
> The "entry fee" is higher initially but the dividend pays back forever.
> 
> The true system requirements will depend on the heat emitters more than anything else. (Think large and low temp with corresponding wide T.)
> ...


I would like to know how to find the best WTAHX for my system (one with a wide delta T) but there doesn't seem to be a lot of options. I was considering Valutech but I was I haven't had a chance to call them to inquire about the design delta T for those units. I am under the impression from other threads that, in general, WTAHX  have narrow delta T specs, like 10 or 15. Anyone know where to get 40? Stack 2 on top of each other?


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## Karl_northwind (Jan 13, 2016)

go to flatplateselect.com  GEA makes all sorts of cool sizes, like 5x20 heat exchangers that will give you really close approach temps.

If you want, PM me with your outputs from flatplateselect.com and I'll look over them for you to make sure things make sense.


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## Karl_northwind (Jan 13, 2016)

go to flatplateselect.com  GEA makes all sorts of cool sizes, like 5x20 heat exchangers that will give you really close approach temps.
if you want, PM me with the outputs from there and I'll look them over to make sure they make sense.


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## Antman (Jan 14, 2016)

Karl_northwind said:


> If you do the Logstor 1.5" you have a better situation than 1.5" Uponor.  1.5" logstor has an ID of 1.6" ID, better than the number I was using.  if you do to and from the GB with 1.5" to house #1, you have a head loss of 11' at 600LF of pipe and 15 GPM.
> that's way better.
> house 2 at 600 feet would need lower flow rate most of the time, as the floor loops can mix the temp down to 100F probably.
> you won't use one pump to pump the entire 900 feet with house 2, you'd use one pump to move the 600' of 1.5" pipe, and do as maple suggested, connect a pair of closely spaced tees with another circulator pushing thru the floor loops when there is a heat call for any particular zone.   or you use a flat plate heat exchanger in the building (could be either the GB or house 1) and run the heating loops pressurized. (as a contractor this is what I would do, because if there are air problems in the floor loops, I have to go back and fix it and that costs the price of a heat exchanger the first time I have to go back.)
> ...


I did read both of Dan's books and idronics and I have to say that, considering the 23' rise on the highest point of house 1 along with the benefits of a closed and pressurized system, I makes sense to go ahead and pressurize in the Garn Barn.

On another note, I inquired what size fittings come on the logstor 1.5" dualpex (1.6" ID) and I was told the compression fittings are 1-1/2" MPT. I'll have to call back to clarify that there is no bottleneck because the submittal sheet for uponor's version of 1-1/2" MPT indicates the ID of 1-1/2" WIPEX MPT compression fitting is 1.24" which would create a bottleneck in 4 places, right? One bottleneck at each end of both underground lines. How much this would impact the system's performance?

Since I'm trying to maximize the system's performance, I'm reconsidering trench and foam. 2" hepex with 2" WIPEX (both ID 1.6") would eliminate the 1.24" bottlenecks. The trench and foam method would take longer but seems that it could be better - more R value, less head loss, and more maneuverable. I'm 99% certain I can make it water-tight. I'll post the bluemax/fiber/XPS demonstration when I get time later today. How much of a difference in performance would I see having the 2" WIPEX over 1-1/2" WIPEX?


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## Antman (Jan 14, 2016)

Hope this demonstration transfers OK. Bluemax/fiber/XPS for trench and foam


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## Karl_northwind (Jan 14, 2016)

either will be fine.  the ID over the long distance is what's going to kill you.  the couple restrictions in the joints won't matter.  the 2" hepex and foam will be cheaper by a long shot than the 1.5" logstor.  and probably just as good if your ground doesn't move much if at all. 

I don't know what wipex is, but 1.5" ID smooth pipe for 600' at 10 gpm and 30 deg delta T = 150,000 btu and 5.5' head. 
1.25" ID smooth pipe for 600' at 10 GPM and 30 degree delta T= 150,000 btu and 12 feet head.  
1.00 ID smooth pipe for 600' at 10 GPM and 30 degree delta T= 150,000 btu and 31 feet head.  

I'd split the difference and get the 1.25, and use a Taco 0015 on high or viridian VT 2218. for each zone with the check valve between the supply and return tees as above, and a 0015 on low to keep the pipes hot and move water thru the DHW HX.  when one or both the Fan coils turn on,  it'll add it's head to the slow 0015 primary circulator, but use minimal energy for the 24-7 pump, and not start pumping cold water thru the air coils. it'll have hot ready for you.


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## Antman (Jan 26, 2016)

For my underground lines, I think I'll use 2" Hepex (1.629" ID) for house 1 (500' primary loop) because it really isn't that much more expensive than the 1.5" Hepex (1.244" ID). I already have 1.25" Hepex (1.054" ID) for house 2 (600' primary loop). My plan is to wait until spring or summer to trench and foam both underground runs when the outside conditions are optimal (dry and 85F). In the meantime, can anyone suggest the best way to bring the lines into the attic through a wooden soffit? I am anticipating 2-3' lengthening of the hepex at 180F for each home. I'm curious if this lengthening and expansion of the underground lines disrupts the closed cell polyurethane foam (PUF) in a trench and foam application any more than the pre-insulated products? I plan to do as Tennman suggested with 6mil plastic (1' wide by 2' deep trench, high voltage line in the bottom, backfill, 6mil plastic, 4" PUF, lay down lines, additional 4" PUF, overlap 6mil plastic and waterproof the joints using blumax/fiber, goal is 1' x 1' x 550' = 550 cu ft or 6,600 board feet PUF for both runs combined).


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## JohnDolz (Jan 28, 2016)

jebatty said:


> Thanks for the interest -- 23 days of riding, 25 days total. Shortest mileage day was 23 and longest was 97. Average/day was 65 miles. Temperatures ranged between a low of 28F (two mornings) and a high of 94F. The trip was solo, self-supported. Bicycle plus packs, gear, food, water was about 105 pounds. An amazing adventure for a 66 year old guy. This link covers a quick summary of most of the trip: Rolling
> 
> I am narrowing down on a destination for another trip in 2016.


Head to San Diego. I can connect you with a ton of folks older than you, all training as if they are heading to the Tour.


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## Karl_northwind (Jan 29, 2016)

Antman said:


> For my underground lines, I think I'll use 2" Hepex (1.629" ID) for house 1 (500' primary loop) because it really isn't that much more expensive than the 1.5" Hepex (1.244" ID). I already have 1.25" Hepex (1.054" ID) for house 2 (600' primary loop). My plan is to wait until spring or summer to trench and foam both underground runs when the outside conditions are optimal (dry and 85F). In the meantime, can anyone suggest the best way to bring the lines into the attic through a wooden soffit? I am anticipating 2-3' lengthening of the hepex at 180F for each home. I'm curious if this lengthening and expansion of the underground lines disrupts the closed cell polyurethane foam (PUF) in a trench and foam application any more than the pre-insulated products? I plan to do as Tennman suggested with 6mil plastic (1' wide by 2' deep trench, high voltage line in the bottom, backfill, 6mil plastic, 4" PUF, lay down lines, additional 4" PUF, overlap 6mil plastic and waterproof the joints using blumax/fiber, goal is 1' x 1' x 550' = 550 cu ft or 6,600 board feet PUF for both runs combined).


it'll add a little pipe, but make a large wide arc with the piping.  the bottom of that run will move quite a bit, and turning that 90 up the wall won't help. 
swing the pipe out from the wall at 90 degrees to the eventual direction, and curve it toward the other end point, and that arc will absorb a lot of that expansion.  a piece of drain tile or 2 around it in that are will provide some air space for the pipe to push against rather than just soil.  that's just thinking, not something I've ever had to do.  I've always had enough curves in the pipe that it could move a little. 
karl


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## Antman (Feb 7, 2016)

I have a 500' primary loop which is predominately underground. I think I can use 1-1/2" hepex but I am trying to determine if 2" hepex to minimize head loss in this long loop could possibly be too large? On page 15 of the Garn Design Manual a 2" nominal plastic pipe intersects 0 at what appears to be ~12 GPM and ~1 or 2 FPS. Does this mean I can only operate the primary circ at 12 GPM or higher? What problems would I have with velocities of less than 1 FPS?


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## Karl_northwind (Feb 8, 2016)

bubbles will collect at high spots.  There is such a thing as too big a pipe.  it may not cause you any problems, depending on lots of things like how your system is piped and where you have air elimination points.  or it may.


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## Bob Rohr (Feb 8, 2016)

Once you drop below 2 fps,the water doesn't entrain the air bubbles as well and getting all the small micro-bubbles purged may be a challenge, especially if you have any ups and downs in the piping.  If the small bubbles collect and form a large bubble you could get an air lock.


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## Antman (Mar 10, 2016)

Karl_northwind said:


> either will be fine.  the ID over the long distance is what's going to kill you.  the couple restrictions in the joints won't matter.  the 2" hepex and foam will be cheaper by a long shot than the 1.5" logstor.  and probably just as good if your ground doesn't move much if at all.
> 
> I don't know what wipex is, but 1.5" ID smooth pipe for 600' at 10 gpm and 30 deg delta T = 150,000 btu and 5.5' head.
> 1.25" ID smooth pipe for 600' at 10 GPM and 30 degree delta T= 150,000 btu and 12 feet head.
> ...



I appreciate your idea of constantly circulating through two 5x12(20) FPHX with a 0015 on low. Could you look at my redrawing to clarify if this is what you were describing? Also, if I were to go ahead and put the water to water FPHX at the highest point in the system, couldn't I put air vents on both sides of it ( a manual one on the open side and an automatic on the closed side) to take care of any problems with air lock associated with the low velocity on the open side that comes with using 1.6" ID buried pipe?


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## Karl_northwind (Mar 11, 2016)

Antman said:


> I appreciate your idea of constantly circulating through two 5x12(20) FPHX with a 0015 on low. Could you look at my redrawing to clarify if this is what you were describing? Also, if I were to go ahead and put the water to water FPHX at the highest point in the system, couldn't I put air vents on both sides of it ( a manual one on the open side and an automatic on the closed side) to take care of any problems with air lock associated with the low velocity on the open side that comes with using 1.6" ID buried pipe?


if your primary loop is short, I think you'll be fine.  the parasitic losses of a long piece of pipe like that will be high.  
really I was thinking that your whole distribution system in the house you wanted to be open.  your design as planned would probably work fine (without looking at it too closely) I would move the return sensor on the 0013 VDT closer to the Flat plate hx.  it'll respond really slowly as is.  
karl


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## Antman (Apr 16, 2016)

Many thanks to the great guidance here. I am firming up my design and looking to trench and foam in 10mil plastic wrapped and sealed with bluemax liquid rubber as soon as the outside temps are ideal (at least 85F). I need to clarify one more thing and is has to do with the supply pump. Is there any reason I can't place it 250' from the Garn hot water supply (HWS) where the pipe comes back out of the ground and into the FPHX? If this is possible, is there a minimum distance a pump can be from the FPHX? I'm assuming not, because I've never come across a minimum distance on a distribution side. Just wanted to get feedback from the experts on this issue or any other concerns with my schematic. Thank You.


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## leon (Apr 16, 2016)

Hello Antman,

Contacting a hydronic circulator specialist at B+G or TACO and go from there as you can very easily 
put your circulator on a reversing timer to push the same water back and forth using a smaller single pipe pex in insulated solid ADS tubing 

Chatting wit B+G or TACO sales representative is going to solve this for you the first time and avoid spending extra money.  

This is the only way your going to solve your current piping issues. I would also upload your
drawings to www.heatinghelp.com if you are now a member.They are all plumbers
over there and will help you too.


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## Karl_northwind (Apr 17, 2016)

Antman said:


> Many thanks to the great guidance here. I am firming up my design and looking to trench and foam in 10mil plastic wrapped and sealed with bluemax liquid rubber as soon as the outside temps are ideal (at least 85F). I need to clarify one more thing and is has to do with the supply pump. Is there any reason I can't place it 250' from the Garn hot water supply (HWS) where the pipe comes back out of the ground and into the FPHX? If this is possible, is there a minimum distance a pump can be from the FPHX? I'm assuming not, because I've never come across a minimum distance on a distribution side. Just wanted to get feedback from the experts on this issue or any other concerns with my schematic. Thank You.


Generally, you'll want the circulator as close to the GARN as possible.  There is math in the Garn design manual for calculating out the NPSH available for your circulator in any location.  I would keep the circulator (unless there is some other overpowering reason) as close to the GARN as possible.  The GARN in your place is the point of no pressure change, and you want to pump away from that, and as close as possible to it.  

off hand, I'd throw a check valve in the primary loop between the supply piping and the return piping.  this will keep the supply piping from pulling backwards thru that connection.  and make sure you have flow checks in all the branch circulators.


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## Antman (Sep 26, 2016)

Karl_northwind said:


> I just did my first set of foamed in place lines, (copper)  and the price was really reasonable compared to logstor or anything else.  the 1.5" uponor with EP fittings would be fine.  2" might be even better, at a couple bucks a foot higher price.  the foam ran about $5 per foot.  plus $8? per foot for 1.5" pex ($4x2) for $13 a foot you have durn good insulation, durn good flow.
> 
> keep the circulator near the boiler to remove issues with the NPSH on that circulator, and that will help too.
> the 2000 is a little small for that load, but most of the year it'll handle all the load, and part of the year it'll handle most of the load.
> ...



So I have spray foam contractor who is going to help me trench and foam closed-cell PUF next month, but he doesn't want to spray into plastic for some reason and recommends spraying into tyvek house wrap. So rather than fighting with trying to add a layer of plastic around the foam for additional waterproofing, I have decided to spray directly into the ground.

The frost line here is 1' and the water table is listed at 1', although the 2 houses and the trench are on high ground (10-20' higher the the surround farmland) so I doubt the trench will ever be under water. To make it easy on everyone when it comes time to spray, I plan to suspend two 2" hepex lines at 18-20" deep using stakes on either side of a 1' wide x 2' deep trench. At the very bottom of the trench I'll put a 2" electrical conduit for high voltage and two 1" hepex lines for hot and cold water. Then, spray foam the entire bottom half of the trench which puts all the foam below the frost level and gives me a 1'x1' block of closed-cell PUF below any potential ground heaving which really isn't an issue in our relatively warm climate anyway (i.e. 18 degree F day). After the foam has cured, I will add a 1" irrigation tubing for control wiring before backfilling.

My question is this... should I add sand in the trench?

We are near the New Madrid fault line, but otherwise the ground is mostly clay and unlikely to move. I'm just trying to decide if the extra effort of adding sand is worth the risk of attracting water to my PUF block that I'd like to keep dry


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## Buzz Saw (Sep 26, 2016)

I don't think sand will draw water but rather let water drain away.  

Our pond had a sand vein and would never stay full. Until the day we dug it out and repack the trench with clay.  The clay is holding all our water in now. Pond level is up 2' now.

Sent from my SM-G900V using Tapatalk


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## leon (Sep 26, 2016)

Antman said:


> So I have spray foam contractor who is going to help me trench and foam closed-cell PUF next month, but he doesn't want to spray into plastic for some reason and recommends spraying into tyvek house wrap. So rather than fighting with trying to add a layer of plastic around the foam for additional waterproofing, I have decided to spray directly into the ground.
> 
> The frost line here is 1' and the water table is listed at 1', although the 2 houses and the trench are on high ground (10-20' higher the the surround farmland) so I doubt the trench will ever be under water. To make it easy on everyone when it comes time to spray, I plan to suspend two 2" hepex lines at 18-20" deep using stakes on either side of a 1' wide x 2' deep trench. At the very bottom of the trench I'll put a 2" electrical conduit for high voltage and two 1" hepex lines for hot and cold water. Then, spray foam the entire bottom half of the trench which puts all the foam below the frost level and gives me a 1'x1' block of closed-cell PUF below any potential ground heaving which really isn't an issue in our relatively warm climate anyway (i.e. 18 degree F day). After the foam has cured, I will add a 1" irrigation tubing for control wiring before back filling.
> 
> ...


=====================================================================================================

The NEC requires electrical conduit above the water lines if my memory is correct, normally its in separate two trenches with high voltage (600Volts +)

The P waves (pressure waves) from an earthquake will liquify clay soils in a heartbeat, so its a question of what is an acceptable risk fo you with your trench? 

Bedding a utility of any kind on a layer of sand is simple easy insurance.  

The Tyvec is just another layer of insurance for you pipe and conduit run. It would be simple enough to build a box frame on caster wheels to hold it in place as he sprays the foam and move it up as the work progresses.


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## Karl_northwind (Sep 29, 2016)

Antman said:


> So I have spray foam contractor who is going to help me trench and foam closed-cell PUF next month, but he doesn't want to spray into plastic for some reason and recommends spraying into tyvek house wrap. So rather than fighting with trying to add a layer of plastic around the foam for additional waterproofing, I have decided to spray directly into the ground.
> 
> The frost line here is 1' and the water table is listed at 1', although the 2 houses and the trench are on high ground (10-20' higher the the surround farmland) so I doubt the trench will ever be under water. To make it easy on everyone when it comes time to spray, I plan to suspend two 2" hepex lines at 18-20" deep using stakes on either side of a 1' wide x 2' deep trench. At the very bottom of the trench I'll put a 2" electrical conduit for high voltage and two 1" hepex lines for hot and cold water. Then, spray foam the entire bottom half of the trench which puts all the foam below the frost level and gives me a 1'x1' block of closed-cell PUF below any potential ground heaving which really isn't an issue in our relatively warm climate anyway (i.e. 18 degree F day). After the foam has cured, I will add a 1" irrigation tubing for control wiring before backfilling.
> 
> ...



You'll find probably that any sort of material is better than bare ground.  the foam gun will blow around all sort of dirt etc, contaminating the foam. My guy won't spray onto bare ground.  tyvek would be OK I guess.  He's probably melted regular poly with the curing temperature of the foam.  

I'd do the electrical off to the side, but still at least 18" to the top of conduit, more under a driveway.  I always run extra conduits etc.  
sand is OK for drainage, but I'd use pea gravel or 3/4" washed rock if you have it available.  but make sure you're not draining it towards your house.  

karl


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## Antman (Dec 14, 2016)

It's been a long summer and we installed underground lines and built a chase to get 2" Hepex into the attic. The Hepex was converted to 1-1/2" Hepex once in the attic. We are planning to build the manifold at the highest point in the attic.

Will the manifold diagrammed here hydraulically separate the primary and secondary?


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## Karl_northwind (Dec 15, 2016)

Antman said:


> It's been a long summer and we installed underground lines and built a chase to get 2" Hepex into the attic. The Hepex was converted to 1-1/2" Hepex once in the attic. We are planning to build the manifold at the highest point in the attic.
> 
> Will the manifold diagrammed here hydraulically separate the primary and secondary?


yes, but it will not necessarily separate the secondaries from each other.  to do that you want to get the manifold flow rate under 2 feet per second flow rate at full flow minus one load.


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## Antman (Dec 19, 2016)

At design conditions (100,000 BTUH) when all 3 furnaces are calling for heat, the primary flow rate is 10 GPM and the secondary flow rates are:

zone 1 (WTAHX) = 2.5 GPM
zone 2 (WTAHX) = 3.33 GPM
zone 3 (WTAHX) = 4.17 GPM

So, if I understand you correctly, "full flow minus one load" (i.e. minus zone 1) = *7.5 GPM*

referencing http://www.engineeringtoolbox.com/pressure-loss-steel-pipes-d_307.html

7.5 GPM through 1-1/2" steel pipe is ~*1.24 f/s*
7.5 GPM through 2" steel pipe is ~*0.74 f/s*

Additionally, I am planning 4 other zones:

DHW + sidestream towel warmer with monoflow tees and trv (constant flow, entire heating season)
pool (shoulder seasons)
spa (entire heating season)
garage fancoil (only around design conditions which is 18F)

I guess I need to calculate these additional flows but it looks like I'll be building the manifold using 2" tees and nipples to try to hydraulically separate the secondary loads.

Am I on the right track? Also, where do you get the 2 ft/s because I referenced 4 ft/s from Caleffi?

Thank you


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## Antman (Dec 22, 2016)

Could I please get suggestions/feedback on my thoughts for boiler and primary pumps:

P1 --> 0013-VDTF3 (cast iron delta T) for house 1 primary in Garn Barn --> 10GPM@5.57FOH
P2 --> VT2218-HY1-4C1A00 (cast iron setpoint) for fancoil in house 2 --> 3.5GPM@3.96FOH
P3 --> 0010-VSSF3 (stainless steel variable speed setpoint) for the Garn boiler --> up to 18GPM@4FOH (only uses S1) setpoint setting ~180F

OR

P3 --> 0013-VDTSF3 (stainless steel delta T) for the Garn boiler --> up to 18GPM@4FOH (uses S1 and S2) dT setting 5F


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## leon (Dec 22, 2016)

With three circulators as you suggest in the drawing your going to 
have issues with the point of no pressure change even though you 
do not have an air scoop and lots of air bubbles even though its an open system. 

A little help from a B+G or TACO sales rep will solve this for you if you fax them a 
drawing or drawings of your system.

Your trying to circumvent basic laws of hydraulics with your design and your going to lose circulators.


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## Antman (Dec 23, 2016)

leon said:


> With three circulators as you suggest in the drawing your going to
> have issues with the point of no pressure change even though you
> do not have an air scoop and lots of air bubbles even though its an open system.
> 
> ...



My drawing doesn't show air eliminators although I do have those planned for the closed side. The Garn-side of the FPHX is open, but I was under the impression that putting the circ down low would guard against cavitation.


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## leon (Dec 23, 2016)

Even with flooded suction on a circulator you can 
have an entrained air problem and water hammer. I really want to see that you talk 
to the systems engineer from TACO or B+G who is also a sales rep in your state.

Two hours work+- and they will have this system ready for you to install.


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## Antman (Dec 23, 2016)

now that i have my loop lengths I call them. more to come... merry christmas to all!


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## Bob Rohr (Dec 23, 2016)

What about a two pump with zone valve solution?

I'd pump into the Garn, pump mounted low, since it is an open system.

For the distribution a single delta P circulator with two zone valves. Pump away from a single expansion tank and expansion tank


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## Antman (Jan 16, 2017)

Karl_northwind said:


> yes, but it will not necessarily separate the secondaries from each other.  to do that you want to get the manifold flow rate under 2 feet per second flow rate at full flow minus one load.



Nevermind, I found a more recent reference for 2f/s

http://www.supplyht.com/articles/98589-four-approaches-to-hydraulic-separation


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## Antman (Feb 10, 2017)

I


Bob Rohr said:


> What about a two pump with zone valve solution?
> 
> I'd pump into the Garn, pump mounted low, since it is an open system.
> 
> For the distribution a single delta P circulator with two zone valves. Pump away from a single expansion tank and expansion tank



Garn recommends dropping the supply line down and pumping away from the water level of the Garn (which approximates the PONCP). I am curious why you recommend putting on the return? Does it have to do with cooler temps on the boiler pump and do you see it as pumping toward the PONPC?

And, thank you very much for your diagram. Could anyone please comment on whether a delta P pump with zone valves in the Garn Barn in any way simplifies and hopefully eliminates the need for 300 ft underground control lines as opposed to just using delta T circs which seems to necessitate underground control lines?


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## maple1 (Feb 10, 2017)

'Control lines'?

Are stat wires control lines? Cause I think you would need wires between the thermostats in the house, and the zone valves in the barn?

But if the zone valves & dP pump were in the house, you shouldn't need wiring between the house & barn - I don't think.


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## Antman (Feb 13, 2017)

maple1 said:


> 'Control lines'?
> 
> Are stat wires control lines? Cause I think you would need wires between the thermostats in the house, and the zone valves in the barn?
> 
> But if the zone valves & dP pump were in the house, you shouldn't need wiring between the house & barn - I don't think.



By control lines I mean the wires that will turn on the pumps in the Garn Barn - I guess those would be stat wires underground if I were to put delta T circs to each of the houses in the Garn Barn. I cannot see any way to run lines underground that far, although I do have several extra pex lines if I need.

What I am trying to determine is whether or not putting a single delta P circ in the Garn Barn as suggested by Hot Rod, could that eliminate having to put control lines underground?

So, if I have a dP circ like the Taco Viridian VR 3452 in the Garn Barn, could I put a zone valve in each house (each 300' away from the Garn Barn) such that when there is a call for heat in one of the houses, its zone valve opens and the VR 3452 ramps up by sensing the change in pressure due to that zone valve opening?

If so, could I then put a flow switch in the Garn Barn which would trigger the boiler circ (0010 setpoint circulator) and this would eliminate the need for any 300' underground triggering wire?

I am open to any other suggestions. Thank you


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## Antman (Feb 14, 2017)

The specific feedback I am looking for is:

1. What kind of cable should I put in my 300' underground runs to start the primary circ in the Garn Barn?
2. Could that same cable also start the boiler circ or would it be better to have a flow switch triggered by the primary circ start the boiler circ?


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## Antman (Sep 27, 2017)

I put a SS boiler pump down low on the return side of the open loop back to the Garn. I have pressurized the manifold and fixed all leaks on both the open side and closed side of the heat exchanger. Can the glycol feeder be used to clean the pipes before filling? If so, how? Any suggestions on cleaning solutions down here in the Memphis area? Can anyone see any glaring problems with my plumbing before I start filling?


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## Antman (Sep 27, 2017)

Also, can anyone suggest what kind of wire to run 300' underground to be used for 24v controls, please?


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## leon (Sep 27, 2017)

Antman said:


> View attachment 200606
> View attachment 200606
> View attachment 200607
> View attachment 200608
> ...


-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



I would just use water and check your strainers more often if you are worried about cleaning your piping.


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## leon (Sep 27, 2017)

Antman said:


> Also, can anyone suggest what kind of wire to run 300' underground to be used for 24v controls, please?




============================================================================

16 gauge stranded wire but I would not do anything until you compensate for line drop of at least 10% so you may not be able to manage the needed 24 volts AC.

Your going to have to talk to an electrical wire supplier to be sure as the line drop power loss is the major issue.


Edited to correct my mistake.


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## Antman (Sep 28, 2017)

leon said:


> ======================================================================================================
> 
> 16 gauge stranded wire but I would not do anything until you compensate for line drop of at least 10% so you may not be able to manage the needed 24 volts DC.
> 
> Your going to have to talk to an electrical wire supplier to be sure as the line drop power loss is the major issue.


I have contacted a couple of HVAC friends and electrician, and, to clarify, the controls are 24V AC


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## surefire (Nov 5, 2017)

Antman, thanks for this thread.  It's been informative and watching your planning and attention to detail has been an inspiration.  It's exciting to see your project progressing; please keep the photos coming!


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## Antman (Nov 14, 2017)

We are about to finish the distribution system but could someone please answer this - can I use a single FPHX to keep both tanks shown here in series hot? I was planning to insert a 20 plate FPHX between the blue valve at the cold water inlet and the first hot water tank but I wasn’t sure if it would heat both tanks or not?


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## Buzz Saw (Nov 14, 2017)

Antman said:


> We are about to finish the distribution system but could someone please answer this - can I use a single FPHX to keep both tanks shown here in series hot? I was planning to insert a 20 plate FPHX between the blue valve at the cold water inlet and the first hot water tank but I wasn’t sure if it would heat both tanks or not?


Are you going to run a circulation pump  to loop the water through the FPHX multiple times to bring the water up to temp?  A single pass through a 20 plate won't be enough to warm the water to 125*(so I've been told).

Sent from my SM-G950U using Tapatalk


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## Antman (Nov 15, 2017)

Buzz Saw said:


> Are you going to run a circulation pump  to loop the water through the FPHX multiple times to bring the water up to temp?  A single pass through a 20 plate won't be enough to warm the water to 125*(so I've been told).
> 
> Sent from my SM-G950U using Tapatalk


Yes I plan to have a circ on the boiler side so that when cold well water replaces the hot water being used at the fixtures, that cold water goes through the FPHX and get heated by the boiler water which will probably somewhere between 150-180F since I have 3  fan coils, a pool and spa tube and shell hx, and a towel warmer, which I think are all high-temp emitters.


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## surefire (Nov 23, 2017)

But will you have a circulator on the Domestic Hot Water side?


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## Antman (Nov 27, 2017)

surefire said:


> But will you have a circulator on the Domestic Hot Water side?


no, i don't have return lines back to the DHW tanks


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## Dutchie84 (Dec 13, 2017)

I'm a sparky not a plumber but with the dhwt hooked in series like that one tank is doing all the work heating the cold water and the other is just acting as a holding tank and coming on to maintaining the temperature if it drops from standby losses.  If you want quicker recovery they should be plumbed in parallel.  As for the fphx it would be heating the water as it enters the first tank but without a circulator on the dhw it wont be maintaining that temperature in either tank.  Is 20 plates enough, I don't know, you may be able to mess around with an online calculator to find out.


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## Antman (Nov 22, 2018)

I have 3 Taco HAFC201 fancoil controls wired between the thermostats and air handlers. They work great but I need help determining how best to complete my dual fuel needs. I want to switch back to propane (hopefully automatically) if the Garn tank temp falls below the usable temperature range. The HAFC201 has contacts for an aquastat on the return line of the fancoil but I am unsure:

1. if the air handlers would automatically switch to propane when temps falls below the aquastat setting
2. which aquastat would work best for this scenario
3. if there is an alternative to using aquastats

Along the same lines, which aquastat or temp probe would be best for the freeze protection contacts which are adjacent to the watercoil contacts?


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## leon (Nov 22, 2018)

The honeywell 8124L1011 triple aquastat relay with conductive paste is the best triple aquastat to use for this to oversee the low limit and high limit temperatures for the propain fired boiler making it completely independent.


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## Antman (Nov 22, 2018)

leon said:


> The honeywell 8124L1011 triple aquastat relay with conductive paste is the best triple aquastat to use for this to oversee the low limit and high limit temperatures for the propain fired boiler making it completely independent.


To clarify, the boiler is wood fired, and the air handlers were propane, and now the thermostats don’t go directly to the air handler. They go to the HAFC201 then to the central heating and AC air handler


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## jwise87 (Nov 25, 2018)

The way I wired mine was by getting an external aquastat that clamped onto the pipe where the water entered the heat exchanger. It was open if temps were above the set point and closed if they were below. On the wiring coming from the thermostat there should be seperate wires to turn on the air handler and the furnace. This aquastat was spliced into the furnace wire so that when the heat was commanded by the thermostat the furnace never recieved the message as long as the water temp was above the set point. It worked great.


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## Antman (Dec 8, 2018)

Can someone give me feedback about my Garn horizontal flue, please? I'm considering converting it to a vertical flue outside the Garn Barn using a tee but I need to know if I'd also have to use a fresh air intake damper to prevent a thermal draft associated with vertical flues. Or, does the presence of a horizontal flue before the vertical flue prevent a draft?


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## TCaldwell (Dec 8, 2018)

Horizontal to a t clean out outside then vertical is a garn approved method. There is a suggested limit length to the horizontal section from the flue collar on the boiler to the t, should be in the manual. A motorized intake air damper that garn sells and is wired to the new style controller is recommended as the draft through the boiler will strip heat.


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## TCaldwell (Dec 8, 2018)

8ft is the max horizontal per the manual


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## Antman (Dec 18, 2018)

jwise87 said:


> The way I wired mine was by getting an external aquastat that clamped onto the pipe where the water entered the heat exchanger. It was open if temps were above the set point and closed if they were below. On the wiring coming from the thermostat there should be seperate wires to turn on the air handler and the furnace. This aquastat was spliced into the furnace wire so that when the heat was commanded by the thermostat the furnace never recieved the message as long as the water temp was above the set point. It worked great.



Thank you for sharing that experience! I couldn't quite envision exactly what you were describing until after I called Taco tech support and the diagram that was provided suddenly seem to make sense. Is this similar to what you did?


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