# Garn It!



## rvtgr8 (Jan 10, 2009)

I have decided to open another thread on my garn installation.  Thanks to so many of the participants, especially Jim K. and Slowzuki, I think that I can safely say that I am seeing light at the end of the tunnel. The details of my plight, of which I am the only one to blame, can be found in the thread, “Garn 1500 Arrived - Can’t afford to hook it up.”  I won’t bother people here with my mistakes.

Okay, the existing boiler in my house is a three year old Burnham - Series 2 (Model B) Gas - Fired Boiler using propane (136 K btu).  I have been unable to find any part numbers or serial numbers. The system includes a sidearm water heater and zoned in-floor radiant heat.  The Pex in the floor is on 12” centers in the middle of 4” reinforced concrete.  There is an insulating layer of Poly-iso foam between the slab and the ground.  The house is three years old, built entirely by my wife and me. 

The house is 2,700 s.f.  It has a steel frame with 8” cavity walls blown solid with cellulose.  I sheathed both inside and outside of the walls with 5/8 OSB. I have 39 dbl pane windows (low E) and have installed dbl walled polycarbonate interior storm windows on each.  We have a Vermont Castings Reliant wood stove which we use to augment the home heating.  We keep the thermostats at 60* year round.  They are standard Honeywell (no frills) units. We have Ponderosa pine firewood for free from our sixty acres.  We are at 7,300 feet, with temps between 90* and -15*. Snows are brutal when they come and many years we have 160”.  We average between 1,400 and 1,500 gals. of propane for the entire year.  Winter takes about 800 - 900 gals. of the total amount.

The design on the current radiant system hooked to the existing boiler is a question mark for a couple of reasons.  The man who designed it did not put in mixing valves.  The boiler appears to be set for a range of 128* to 168*. This is the drawing of the existing system.  Forgive my homespun CAD work.







I have purchased a Garn 1500 and due to budget constraints must install it myself.  I only set aside $2500 and my installer wants $8K.  I am not being critical of the installer.  He believes that it is a fair price, and it may be, but I do not have the cash.

The Garn will be installed in my new boiler room that used to be my garage. The old boiler room is adjacent to the new one so I have only to cut through a single wall to hook into the Garn.  No excavation will be required until some future project comes online. My hot tub and a single radiator will be added into a new room that was my second stall in the garage.  Thanks to Jim K, I have now designed a system that just might actually work with efficiency.  I am including it here.






My first question is how do I deal with the temperatures in my existing system which appear to be too high because of the lack of mixing valves?  Should I place a mixing valve on each of the old zones?  The rooms never over or under heat when we use our boiler.

The next question is about sizing on the primary loop on the Garn.  Is 1¼” black steel sufficient?

This is probably too much for a first post. I am working on questions and an improved drawing of the new system for later.

Fire away!

Robert


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## Sting (Jan 11, 2009)

Cheese and Rice -- With drawings like that -- i should be asking you for advice

Let me take a stab at this on thing

"My first question is how do I deal with the temperatures in my existing system which appear to be too high because of the lack of mixing valves?  Should I place a mixing valve on each of the old zones?  The rooms never over or under heat when we use our boiler."

Simply choke (partially close) one of those fine shutoff valves you have in each zone loop to reduce the amount of energy your sending to the load and create the desired Delta T-- that's a simple way - in place of a nice automatic valve!  -- Now you may have to play with this -- open the valve a "smidge" bit when the primary loop is circulating cooler water in the warmer part of the season and maybe not.

Kind Regards
Sting


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## Jim K in PA (Jan 11, 2009)

Robert,

If the radiator loop you are showing is for a single radiator, then I do not think you need to make a seperate loop just for that.  I would run the return line from your hot tub through a BB rad or an old fashioned cast iron radiator to keep the hot tub area comfortable.  That will simplify things.  I also think you may find that the standby losses from the GARN itself will keep the garage area comfortable, depending on how well insulated the garage is.

As for primary pipe loop sizing, this is really dictated by the total Btu load you need to feed (GPM you need to pump).  However, I would suggest not less than 1-1/2" primary piping, and 1-1/4" secondary piping to the HX for the house.  The greenhouse may also need as much diameter, depending on the heat loss.  Have you done the calcs for it yet?  The hot tub can probably get by with a 1/2" loop, depending on it's size, but I would pipe it with 3/4" for comfort.

Your getting closer!


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## heaterman (Jan 11, 2009)

[quote author="rvtgr8" date="1231631791"]I have decided to open another thread on my garn installation.  Thanks to so many of the participants, especially Jim K. and Slowzuki, I think that I can safely say that I am seeing light at the end of the tunnel. The details of my plight, of which I am the only one to blame, can be found in the thread, “Garn 1500 Arrived - Can’t afford to hook it up.”  I won’t bother people here with my mistakes.

Okay, the existing boiler in my house is a three year old Burnham - Series 2 (Model B) Gas - Fired Boiler using propane (136 K btu).  I have been unable to find any part numbers or serial numbers. The system includes a sidearm water heater and zoned in-floor radiant heat.  The Pex in the floor is on 12” centers in the middle of 4” reinforced concrete.  There is an insulating layer of Poly-iso foam between the slab and the ground.  The house is three years old, built entirely by my wife and me. 

The house is 2,700 s.f.  It has a steel frame with 8” cavity walls blown solid with cellulose.  I sheathed both inside and outside of the walls with 5/8 OSB. I have 39 dbl pane windows (low E) and have installed dbl walled polycarbonate interior storm windows on each.  We have a Vermont Castings Reliant wood stove which we use to augment the home heating.  We keep the thermostats at 60* year round.  They are standard Honeywell (no frills) units. We have Ponderosa pine firewood for free from our sixty acres.  We are at 7,300 feet, with temps between 90* and -15*. Snows are brutal when they come and many years we have 160”.  We average between 1,400 and 1,500 gals. of propane for the entire year.  Winter takes about 800 - 900 gals. of the total amount.

The design on the current radiant system hooked to the existing boiler is a question mark for a couple of reasons.  The man who designed it did not put in mixing valves.  The boiler appears to be set for a range of 128* to 168*. This is the drawing of the existing system.  Forgive my homespun CAD work.






I have purchased a Garn 1500 and due to budget constraints must install it myself.  I only set aside $2500 and my installer wants $8K.  I am not being critical of the installer.  He believes that it is a fair price, and it may be, but I do not have the cash.

The Garn will be installed in my new boiler room that used to be my garage. The old boiler room is adjacent to the new one so I have only to cut through a single wall to hook into the Garn.  No excavation will be required until some future project comes online. My hot tub and a single radiator will be added into a new room that was my second stall in the garage.  Thanks to Jim K, I have now designed a system that just might actually work with efficiency.  I am including it here.






My first question is how do I deal with the temperatures in my existing system which appear to be too high because of the lack of mixing valves?  Should I place a mixing valve on each of the old zones?  The rooms never over or under heat when we use our boiler.

The next question is about sizing on the primary loop on the Garn.  Is 1¼” black steel sufficient?

This is probably too much for a first post. I am working on questions and an improved drawing of the new system for later.

Fire away!

Robert[/quot 


A couple quick thoughts

If all your existing loads are low temp in slab type radiant, install a single mixing valve in the main feeding all of them. Note: you'd want to determine which zone needs the highest temp and set the M/V accordingly.  You may want to incorporate some type of boiler protection for the Burnham at that point also. They have diagrams of several methods in their Heating Helper listed on the Burnham website.
Come to think of it..........Now might be a good time to consider installing a variable speed mixing circ which would temper the water going to the zones and protect your gas boiler.

I think you'd want to isolate the garn on one side of the HX and take your additional loads (greenhouse,tub etc) from the pressurized side of the system. This will prevent O2 infiltration from as much of the system as possible. 

Those are just first quick glance impressions. I'll try to study it further when if I get some time. (doubtful given the weather forecast for next week.    C-C-C-C-Cold


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## rvtgr8 (Jan 11, 2009)

Jim K and Heaterman,

Here is another drawing.  I put the hot tub and radiator on the pressurized house loop.  I replaced my Taco 007 with the suggested mixing circulator and in the process got the system pumping away from the boiler.  If this would work, any suggestion on a model, sz, etc.?  Am I correct in assuming that the Burnham will only fire if the temperature drops below its set range and so as long as I am stoking the Garn, then it will be the only heat source? 

Jim K, I have not figured the needs for the green house yet.  It will be partly passive solar with several thousand gallons of water absorbing btu's during the day and giving them back at night.  I am not going for much more than keeping the thing from going below freezing.  It will be a 24'x48' poly-carbonate job with a well insulated foundation and north wall.

Fire away!

Robert


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## rvtgr8 (Jan 12, 2009)

Another question that I have is  when I Run the hot tub and the radiator on the same zone it should be parallel as I have drawn and not in series? :-S


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## in hot water (Jan 12, 2009)

why not the Garn hx in parallel with the Burnham?  No reason the flow through the un-fired Burnham.

 hr


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## slowzuki (Jan 12, 2009)

Robert I left some Q's in the other thread for you before I noticed this thread.


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## slowzuki (Jan 12, 2009)

I'll try to post my simplification points, we need to solve overall what we are doing before detailing the system:

-The system is working right now, we should be careful about what we are fixing with a mixdown.  If the current system runs anywhere near 100% of the time with the high water temps, we can't reduce the water temp used.  Thats why I'm asking about duty cycle in the other thread.  Also, if it runs well with little overshoot at high temps, and a low duty cycle, we will probably be ok at lower temps and a longer duty cycle.

-All the new small loads are high temp loads, so why should we be making loops that are great for mixing down to lower temps.  We have a huge mixing tank in the Garn that changes temp fairly slowly and all the loads can be designed for some lowest temp that the Garn tank will get down too.  The garn tank is basically a large primary loop with a constant natural circulator.

-That said, the flat plate hx will be the most challenging component.  At low temps in the Garn, if the interior zones are designed to need high temp, the zone valves will be open at nearly 100% duty cycle to get the heat out of the loop and if the gas boiler is left to run off an aqua stat it will turn on whenever the Garn is getting cool while the rooms are still getting enough heat.  I'm guessing a fancier thermostat will be needed or a second one that can call for reserve heat in the gas boiler.  Also an aquastat in the Garn could be used to control the switchover.


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## rvtgr8 (Jan 12, 2009)

Slowzuki, That's the thing, the zones do not run all of the time.  It's 20* out right now with 25 mph winds.  I went out and checked the boiler.  The side arm had no call and was not running.  My back rooms were not running and they are on the same zone.  Two zones kicked in while I was watching and one of those was on the wind side of the house, while the other is our sunroom where we keep our parrots.

We never had the system run at temps over 60* in an attempt to save propane.  I am not able to ascertain how the old system would be impacted by a HX running at higher or lower temps, but I was hoping the the mixing circulator in place of my Taco 007 would give me the flexibility to adjust temps to appropriate levels.  Am I way off base here?

In Hot Water, your intuition was the same as mine initially, but not being an engineer, I have deferred to several  very smart Garngaroos who suggested that I use a primary loop as I have shown.  This is the problem with being a newbie to hydronics, everybody knows so much more than I do.  When I joined, I thought Delta T was a reference to the actress Delta Burke.  I was unaware of her unheralded skills as a boiler maven.


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## Jim K in PA (Jan 12, 2009)

I'll try not to confuse or obfuscate (love that word), so I'll defer to others more competent than I, but I suggest the simplest system usually works best.  Given that Robert has a gas fired boiler with a low set of 128, I think he will be just fine with his GARN running down to 135 before he fires it, and before the low set of the Burnham kicks it on (he can lower it more, perhaps).  

Robert - simplify the primary loop.  You have two pumps where only 1 is needed.  Do not pipe the GARN as a secondary - it should be in series with the primary loop.  Pipe out - pump - secondary load tees - pipe back into GARN.

You left out the circ pump for the GH.  No biggie.

HX sizing will be key.  In order to keep the Burnham from reaching low setpoint when the GARN temps are less than 20 degrees above that set point, the HX must be able to transfer efficiently at those lower temps.  More surface area will be needed.  Size of the HX will be MUCH larger than you might estimate based on peak AVERAGE load.  Instantaneous peaks, where you have most or all zones all calling, wind blowing , shower running, etc., is where you might find the Burnham kicking in to supplement if the HX is not loading enough heat into the house side.  Do you care if the propane unit kicks on 5% of the time?  If not, then no worries.  Honestly, I think with a radiant system, you can get along just fine with short term dips in water temp (minutes, not hours).

I am thinking 70 plate 5x12, at least, for all his present and future loads.  This component will be the next largest single purchase after the GARN itself in your system.  Check eBay for KJmotorsports - he has good prices and shipping is free.  I just bought my 50 plate from Kyle.


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## slowzuki (Jan 12, 2009)

1. That is good, gives you options in your setup.

2. The HX will need to be sized (we'll help) such that on the coldest day with the Garn at the lowest target temp, you can still keep the house at your set temperature.  The lowest temp we can run the Garn down to will be determined by the PEX already in the slab in that once the zone is open and flowing full tilt, a correct hx installed, the only thing you can play with is water temp.

3. Your intuition is right, simpler is better to a point. The primary secondary is a good way of connecting several loads and heat sources that are going to be in use simultaneously without having to think hard.  It lets you look at each one individually and saves creating accidental problems.  It is however not the simplest is some cases.



			
				rvtgr8 said:
			
		

> Slowzuki, That's the thing, the zones do not run all of the time.  It's 20* out right now with 25 mph winds.  I went out and checked the boiler.  The side arm had no call and was not running.  My back rooms were not running and they are on the same zone.  Two zones kicked in while I was watching and one of those was on the wind side of the house, while the other is our sunroom where we keep our parrots.
> 
> We never had the system run at temps over 60* in an attempt to save propane.  I am not able to ascertain how the old system would be impacted by a HX running at higher or lower temps, but I was hoping the the mixing circulator in place of my Taco 007 would give me the flexibility to adjust temps to appropriate levels.  Am I way off base here?
> 
> In Hot Water, your intuition was the same as mine initially, but not being an engineer, I have deferred to several  very smart Garngaroos who suggested that I use a primary loop as I have shown.  This is the problem with being a newbie to hydronics, everybody knows so much more than I do.  When I joined, I thought Delta T was a reference to the actress Delta Burke.  I was unaware of her unheralded skills as a boiler maven.


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## slowzuki (Jan 12, 2009)

1. Agreed simple is better.  I'm not convinced on the existing boiler, I think it will get a bunch of short cycles while the HX comes up to temp from the Garn.

2. The primary loop already existing inside the Garn.  Why try to complicate it?  As long as the Garn has some large diameter tappings, you can install a short fat manifold directly to the Garn.
EDIT I see what you are saying.  I'm sort of saying the same thing.  I was thinking manifold but if you incorperate the HX into a primary loop you can put the new loads on the loop.  That will force the main circulator to run all the time.  Not so good in the summer as it will have more wasted heat.

3. Agreed the HX will be big.



			
				Jim K in PA said:
			
		

> I'll try not to confuse or obfuscate (love that word), so I'll defer to others more competent than I, but I suggest the simplest system usually works best.  Given that Robert has a gas fired boiler with a low set of 128, I think he will be just fine with his GARN running down to 135 before he fires it, and before the low set of the Burnham kicks it on (he can lower it more, perhaps).
> 
> Robert - simplify the primary loop.  You have two pumps where only 1 is needed.  Do not pipe the GARN as a secondary - it should be in series with the primary loop.  Pipe out - pump - secondary load tees - pipe back into GARN.
> 
> ...


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## slowzuki (Jan 12, 2009)

Using a pump or valve to mix down the temps at the house has benefits but I don't think it is a priority right now for getting the system up and running on a minimal budget.  2500$ is gonna take a hit from the flat plate purchase.  And the non-ferrous pumps on the Garn side are fairly pricey too.


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## rvtgr8 (Jan 12, 2009)

Okay, primary loop changed, greenhouse circulator in place and 70 plate HX "in da howse!"  

Slowzuki, were you saying you liked the idea of a mixing circulator pump to control temps in the old system?


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## slowzuki (Jan 12, 2009)

Robert,

Protecting your old boiler with a mixing device or even providing mixed water to your slab are nice features to have, but they are off track of getting your system up and running since it works already.  I'd suggest adding them later after getting the Garn running.  There are a number of ways of doing it and some can move your gas boiler out of the loop in case you don't want it to be heated too.

Your newest sketch is exactly what Jim is talking about.  My suggestion is only to eliminate the loop off the Garn and install a pair of short fat manifolds (one supply, one return) at the Garn and use pumps with flow checks to prevent them from ghost flowing in reverse.  All the Garn zones would be in parallel.


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## rvtgr8 (Jan 12, 2009)

Slowzuki, I just read your comments that you posted on the other thread and have included them here.  I wanted to give you the most accurate picture I can.  I went out to test the system.  This is what I did:

1] again, it is a cold windy day (22* with gusty winds 25mph and 4" snow but now sunny). We have a fire going in our VC Defiant.  Thermostats are all set at sixty.  The house is about 70* with the fire and the solar gain in the sunroom.  As you might expect, there was no heat call anywhere in the house and so the system was inactive, including my trusty Taco 007.  
2] I hand felt all of the zones and they had obviously been off for some time because they were cool.
3] I turned on a utility sink in our mudroom to put a call on our side arm water heater.  After several minutes the boiler came on, the Taco came on and water began to circulate.  The pipes on that zone quickly became too hot to comfortably hold on to. 
4] No other zones came on.
5] There are no noises other than the obvious clicks when the electric valves open.  The Taco is so quiet that I can only hear it when I place a rod on the motor and place my ear on the other end.

Hope this helps

Robert



> Hi Robert,
> I think it is entirely reasonable to achieve what you want to do on the budget, the question will be how fancy to get with it, and how many of the other toys you want to hook in immediately.  I’ve got a few questions for you about your current setup so we can help you more.
> 
> When it is cold out, do you know roughly what percentage of the time your circulator runs or zone valves run?  Since you have basic thermostats I’m assuming it is wired to open the zone valve and start the pump or it may be wired to run the pump continuous and the t-stat just runs the zone valve.
> ...


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## rvtgr8 (Jan 12, 2009)

Ken, is this sort of what you are talking about?


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## Jim K in PA (Jan 12, 2009)

Ken - you and I are now in full understanding of each other, I think.  I think you and I are skinning the cat in two slightly different ways, but getting to the same point.  As far as the primary pump having to run continuously, that is not necessarily so.  I solved that issue with a TACO Zone Valve Controller and a TACO Switching Relay Controller.  Any zone on the house triggers the end switch on the ZVC, which then triggers the circ on the house loop.  The SRC has an end switch that starts the primary pump whenever any secondary pump is energized.  The units are not cheap, but not bad either (~$190 each).  

I am also not convinced that bronze pumps are an absolute necessity in a GARN application.  Although technically an "open" system because it is not pressurized, there is no appreciable O2 reuptake unless you are refilling due to a leak.  Standard ferrous pumps are perfectly OK, IMO.


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## slowzuki (Jan 12, 2009)

Hi Robert and Jim,

Robert, you are getting close but not quite.  I'll try a sketch.

Jim, yes, a zone controller could nicely handle the logic of starting the Garn from the calls for heat in the house.  This could also be done with some wiring and a couple of relays but for Robert the controller might be easier.

I also agree the bronze pumps are not required with boiler treatment.  I was thinking of the stainless Garn copy another fellow on here has, normal Garns are steel.  A stainless tank without treatment would end up attacking a ferrous pump.

I'll add a sketch to here in a few minutes.

Ok please take it easy on me, I'm on a broken touch pad, with no mouse!  But you get the idea.  The suction manifold has to be as large as the tapping on the Garn allows and as short as physically possible while allowing the pumps to be a couple of feet lower than the water level so they don't have suction issues.

Each pump is sized by the duty it is doing.  The HX pump will be fairly large.  The start signal for your current large circulator can be sent to an aquastat on the Garn with a low temp cutoff and then to the HX pump so if the Garn is cold the HX pump won't run.


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## rvtgr8 (Jan 13, 2009)

Ken, is this close to what your drawing is trying to illustrate?


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## Rick Stanley (Jan 13, 2009)

I have been cautioned by Garn (the dealer, the manual and Lunde) to keep the Garn pumps as close to the floor as possible and to have 6 ft of black iron between the Garn and the first yellow metal.

Rick


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## slowzuki (Jan 13, 2009)

Robert yes it is.  Thanks for cleaning it up!

Based on what Rick is saying it sounds like the tapping on the Garn might not be very big.  In that case, yes, you need to get you pumps down low so the head from the water in the tank always keeps them from cavitating.  Any one have any info on the Garn's tappings?

Regarding the connection of copper to a steel boiler, in practice its usually ok to connect a small amount of brass or copper to large steel system especially with teflon tape / pipe dope between.  If you have a lot of copper, dielectric unions can help reduce corrosion of the steel, they aren't perfect though.  Cheap brass with lots of zinc in it can have the zinc stripped right out of it as it acts like an anode to the steel.  

Some boiler treatments can reduce the corrosion of metals that aren't compatible, the galvanic potentials of the metals is affected by what electrolyte they are in.


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## Jim K in PA (Jan 13, 2009)

The GARN tappings are 2" upper (supply) and 1.5" lower (return).

The location of the pumps is important, and I may have to lower mine.  I have my primary pump at about 30" above the floor.  If I get the water temps above 195, I start to hear "suction boiling" in the pump.  I usually keep my temps below 190 for that reason.  I will probably re-pipe the pumps lower next summer.  I can actually get my pumps below the bottom of the GARN, as I run them in my garage, the floor level of which is about 3' below grade where the GARN sits.


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## slowzuki (Jan 13, 2009)

Jim do you have 2" with a minimal number of fittings up to the suction side of your pumps and is your main pump high capacity?  It doesn't take many fittings to add friction.



			
				Jim K in PA said:
			
		

> The GARN tappings are 2" upper (supply) and 1.5" lower (return).
> 
> The location of the pumps is important, and I may have to lower mine.  I have my primary pump at about 30" above the floor.  If I get the water temps above 195, I start to hear "suction boiling" in the pump.  I usually keep my temps below 190 for that reason.  I will probably re-pipe the pumps lower next summer.  I can actually get my pumps below the bottom of the GARN, as I run them in my garage, the floor level of which is about 3' below grade where the GARN sits.


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## rvtgr8 (Jan 13, 2009)

Rick, your concern is not only noted, but much appreciated.  Thank you for your interest.  
Robert


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## Rick Stanley (Jan 13, 2009)

Robert, I've been asking dumb questions in here for so long that I can actually contribute some, at times. That's what makes this a cool place.


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## Jim K in PA (Jan 13, 2009)

slowzuki said:
			
		

> Jim do you have 2" with a minimal number of fittings up to the suction side of your pumps and is your main pump high capacity?  It doesn't take many fittings to add friction.



Ken - in a moment of haste, I bushed the outlet of the GARN down to 1.5".  I have two 90s before the Grundfos 43-44, which is a high volume, low head pump.  After the pump there are 5 more elbows and a brass flapper one way valve.

I thought about going 2" all the way to the pump, and then stepping down at the outlet flange or after the next elbow.  I was so far behind schedule wise I piped it all in 1.5" just to get going.  Part of the learning process. 8-/


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## rvtgr8 (Jan 15, 2009)

This drawing is pretty lame and needs some explanation.  The next post will show boiler placement and should help this pic. make sense.

My Garn is in the first stall of the garage that is no more.  My boiler room is directly adjacent to the Garn.  I will be bringing the Garn hot water out and down to the garage floor, swing to the side of  it and go straight through the wall into the existing boiler room and  into the the  manifold hung on the wall.  I have drawn the manifold in the box in the upper right side of the picture. The pipe will be full 2" black steel for a full 8' before any circ motor.  The HX a full 90 plate miracle of manufacturing.  I have not yet sized the circulating pump and will solve the mixing problem as soon as I decide on the placement of the manifold


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## rvtgr8 (Jan 15, 2009)

This is the placement that goes with the manifold drawing.  Am I getting warmer?
Robert


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## slowzuki (Jan 15, 2009)

I'll try to run some numbers but you may need to go up to 2.5" if having 8 ft of pipe plus fittings before the pump but that layout is the simplest way to do it.


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## rvtgr8 (Jan 15, 2009)

Slowzuki,

I can't thank you enough for taking the time to look at this problem.  I do have a question on your last posting and please forgive my ignorance, but if the hot water that leaves the Garn comes out of a 2" tapped hole, won't the 2.5" steel pipe be bottlenecked and thereby less effective?  Perhaps I need to place the manifold on the garage side of the system where it has less black steel before the circulators.  I was under the impression that a minimum of 6' of black steel should be maintained before I put in my first pump.  Can a pump with metals that allow for less corrosion (i.e. non-brass) be inserted closer to the Garn which would eliminate the need for this 6' problem?
I hope I am not sounding too idiotic.

Robert


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## slowzuki (Jan 15, 2009)

I think what Garn is trying to do with their copper/brass rules is to try to have any galvanic corrosion from the interface of the two metals occurs in the pipe and not in the boiler or welded outlet where it is difficult to repair.  The iron/steel pumps are the cheapest ones and can be put as close as you like (well, assuming fairly normal sized circulators.) 

The 2" tapping does reduce the effectivemess of a 2.5" pipe a bit, but it is far better than using 2" pipe.


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## Jim K in PA (Jan 15, 2009)

slowzuki said:
			
		

> I
> The 2" tapping does reduce the effectivemess of a 2.5" pipe a bit, but it is far better than using 2" pipe.



Effectiveness in terms of ????  Cavitation?  Unless he oversizes the circs on all the legs, I can't imagine he would run out of GPM capacity in a 2" pipe given his intended loads.  If Robert places the supply manifold and pumps near the floor, that should give him over 5' of NPSH.  Bigger pipe won't increase NPSH.

I'm trying to figure out how to re-pipe my own supply leg while working out yours, Robert.  I hope you don't mind . . .  :red:


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## rvtgr8 (Jan 15, 2009)

Ken,

Thanks for clearing that up for me.  Do you believe the increase in size would get me into the boiler room or should I plan on having the manifold on the outside of the Garn containment enclosure?  In addition, the return port on the Garn is even smaller than the 2" hot side.  Can I assume that the whole manifold loop would be plumbed in the 2.5" steel?


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## rvtgr8 (Jan 15, 2009)

Jim,

I looked at the flow rates on the difference between 2" and 2.5" pipe and it seems significant in terms of actual flow.  I lowered the pumps for the cavitation problem. A 90 plate HX on 2" looks like I can deliver almost the full monty from the Garn (500K+ btu) to the existing system which is rolling along with a Burnham capable of producing 136K btu's.  I realize that I will have future loads, is it your opinion that my exchanger should be sized for the maximum amount of output?

PS - No worry about sharing the thread.


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## slowzuki (Jan 15, 2009)

Jim/Robert, I just checked some quick numbers and you should be good with the 2" as long as you don't go crazy with elbows.  Jim, bigger pipe will increase the NPSH available at the suction because it reduces the friction loss.  Its far more important to control friction loss on the suction than discharge.  You can't fix cavitation, but you can pay for increased pumping costs/more powerful pump to solve the other side.

Robert, a 2" return to the tank is a good idea.  If you are guaranteed to have all high head circulators it wouldn't matter much but by making it large, it will reduce problems with choosing circulators in the future once you add loads.  Besides, it will save you a bit of power while running your circs.


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## slowzuki (Jan 15, 2009)

Robert, could you share the 90 plate info you have for sizing?  I've not sized a HX for a while and don't want to steer you wrong.



			
				rvtgr8 said:
			
		

> Jim,
> 
> I looked at the flow rates on the difference between 2" and 2.5" pipe and it seems significant in terms of actual flow.  I lowered the pumps for the cavitation problem. A 90 plate HX on 2" looks like I can deliver almost the full monty from the Garn (500K+ btu) to the existing system which is rolling along with a Burnham capable of producing 136K btu's.  I realize that I will have future loads, is it your opinion that my exchanger should be sized for the maximum amount of output?
> 
> PS - No worry about sharing the thread.


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## Jim K in PA (Jan 15, 2009)

slowzuki said:
			
		

> Jim/Robert, I just checked some quick numbers and you should be good with the 2" as long as you don't go crazy with elbows.  Jim, bigger pipe will increase the NPSH available at the suction because it reduces the friction loss.  Its far more important to control friction loss on the suction than discharge.  You can't fix cavitation, but you can pay for increased pumping costs/more powerful pump to solve the other side.



Thanks Ken, I was only considering volume, not friction loss.



> Robert, a 2" return to the tank is a good idea.  If you are guaranteed to have all high head circulators it wouldn't matter much but by making it large, it will reduce problems with choosing circulators in the future once you add loads.  Besides, it will save you a bit of power while running your circs.



The reduction to 1.5" at the tank won't negate the gain of the 2" primary piping?


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## slowzuki (Jan 15, 2009)

Nope it won't negate it.  It will be the largest single loss in the loop though.  The shape of expanding to 2" does create a larger loss at that single point than leaving 1.5" but you make it back in the pipe and fittings loss.  You don't have to use 2", especially if you don't plan on adding a lot of zones right off the boiler.


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## rvtgr8 (Jan 15, 2009)

Ken, 
This is stainless steel one.  There is one listed on ebay from the same store for half the price that has more copper in it.  I don't know if short cuts are wise on the HX Trail.

http://www.flatplate.com/pdf/hydronic/FPbrochure9-99.pdf


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## slowzuki (Jan 15, 2009)

Hmm, I'll have to dig out my heat transfer texts to calc that.  They don't give enough info to size it.


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## rvtgr8 (Jan 15, 2009)

Ken,

I fixed my last post.  I put in the image instead of the address for the whole pdf.  My bad.  Should be plenty of information now.


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## slowzuki (Jan 15, 2009)

There is info but you still need to use a formula, they don't provide enough tables to size from their documents.


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## Jim K in PA (Jan 15, 2009)

Robert - I do not think you need more than the standard FP series unit.  The FPN (nickel plated) is for solvent apps, and the MP (multipurpose) series is for marine and pool (Chlor/Bromine apps).

Ken - http://www.flatplate.com/resources_SOFT.htm is the sizing application that is free to use at GEA's web site.  You have to register, but it is worth it.  

As far as sizing, I think the 90 will exceed what you need substantially, but you will be able to get decent efficiency of heat transfer even as the delta T between the load (house et al.) and the supply (GARN) get closer.  That is an expensive unit.  Here is an 80 plate with 1.25" fittings that is $785 - http://cgi.ebay.com/GEA-Flatplate-B...20598QQcmdZViewItemQQ_trksidZp1742.m153.l1262


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## rvtgr8 (Jan 17, 2009)

Would a Taco Cast iron 0010-ZF3 flanged out to 2" work on the Garn loop to drive the hot tub, a single old fashioned radiator 12"W x 48"L x 24" T and a 90 plate HX to the old system?


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## Jim K in PA (Jan 18, 2009)

Robert - I do not have my TACO pump curves handy, but I think the 0010 is plenty.  But why not put a valve and pump on the hot tub load, and have the big TACO take of the HX by itself?  How will you regulate flow through the hot tub loop?  A TACO 007 or Grundfos 15-58 is cheap, under $80 via eBay or Pexsupply.com.


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## rvtgr8 (Jan 19, 2009)

Jim,

I have the opportunity to buy two of the the Taco 0010 ZF3's new in the box for $200.  I guess I could use the other one for the hot tub and radiator.  Or do you think that that is too much power on the HT loop?


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## Jim K in PA (Jan 19, 2009)

rvtgr8 said:
			
		

> Jim,
> 
> I have the opportunity to buy two of the the Taco 0010 ZF3's new in the box for $200.  I guess I could use the other one for the hot tub and radiator.  Or do you think that that is too much power on the HT loop?



Robert - CL add?  Those ZF3 pumps are probably not what you want.  According to the specs (http://kingsolar.com/catalog/mfg/taco/0010zf3.html) They will only flange up to 1.5".  I thought you were going with 2" on your primary manifold.  They are WAAAAAy too much flow for the hot tub secondary loop.  They are high flow, relatively low head pumps.  So, they will be overkill for the HT, but may not be happy with the amount of head loss through the HX.

Those pumps also have integrated switching relay controllers, which you may not want.  They are also single speed.

Final thought - yes, you could buy them and use them, and they may work, but consider the above.  Sometimes a deal is not such a deal.


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## BrownianHeatingTech (Jan 19, 2009)

Jim K in PA said:
			
		

> According to the specs (http://kingsolar.com/catalog/mfg/taco/0010zf3.html) They will only flange up to 1.5".  I thought you were going with 2" on your primary manifold.



Reducing down to 1.5" just prior to and after the pump would not significantly impede flow.

Joe


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## rvtgr8 (Jan 19, 2009)

Jim and Joe,

You guys are the greatest.  I do have a couple of questions.  

1] is $100 a good price on the 0010?
2] If it is a good price should I buy the other for backup or the future greenhouse loop? 100' away on 1.5" pex
3] Would it harm the hot tub loop with the old fashioned radiator or should I go for a 007?
4] Where do you get your capes?  We have no super heros here in Elbert.


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## Jim K in PA (Jan 19, 2009)

rvtgr8 said:
			
		

> Jim and Joe,
> 
> You guys are the greatest.  I do have a couple of questions.
> 
> 1] is $100 a good price on the 0010?



Pexsupply.com shows a "regular" 0010 going for around $200 each.  I think the price is definately right on those CL pumps.  I am just not convinced those are the right pumps for you.  Perhaps Joe has some insight.



> 2] If it is a good price should I buy the other for backup or the future greenhouse loop? 100' away on 1.5" pex



Here is the TACO official spec page for that pump: http://www.taco-hvac.com/uploads/FileLibrary/100-20.pdf  As long as you are not exceeding 9 feet of head, you should be fine.  However, given you have 200' of pipe (supply and return) plus the radiant(?) tubing in the GH, plus fittings, you will likely be at or beyond the max 9' capacity of this pump for the GH.  Here is a chart on head loss for PEX and Cu tubing: http://www.cozyheat.net/MTR/tubing/pdf/headloss.pdf  Just the 1.5"piping (in copper) will give you about 4' head loss if you are pushing 100k Btuh (have you done a heat load calc for the GH?  They consume a lot of heat)



> 3] Would it harm the hot tub loop with the old fashioned radiator or should I go for a 007?



Possibly, due to the high velocity.  Erosion of fittings starts to occur at high flow rates, plus it makes more noise (you may not care).



> 4] Where do you get your capes?  We have no super heros here in Elbert.



I like warm apples on my crepes.   Sometimes IHOP has a special . . . ;-) 

For future controllability, you may want to consider a 3 speed pump like the Grundfos or Wilo.


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## BrownianHeatingTech (Jan 20, 2009)

Jim is right - the 0010 is for primary loops, not really for delivery of water to zones.  It produces high flow, but very little head.

Joe


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## rvtgr8 (Jan 21, 2009)

Jim, do you have a model number on these two units?  I go before the building inspector tomorrow to run some of my changes past him.  He will be asking me how the Garn gets the word when it needs to join the party.  Also, I took your advice on the smaller Grunfos for the hot tub and am looking to use the 0010 on the primary loop.


> Ken - you and I are now in full understanding of each other, I think.  I think you and I are skinning the cat in two slightly different ways, but getting to the same point.  As far as the primary pump having to run continuously, that is not necessarily so.  I solved that issue with a TACO Zone Valve Controller and a TACO Switching Relay Controller.  Any zone on the house triggers the end switch on the ZVC, which then triggers the circ on the house loop.  The SRC has an end switch that starts the primary pump whenever any secondary pump is energized.  The units are not cheap, but not bad either (~$190 each).
> 
> I am also not convinced that bronze pumps are an absolute necessity in a GARN application.  Although technically an “open” system because it is not pressurized, there is no appreciable O2 reuptake unless you are refilling due to a leak.  Standard ferrous pumps are perfectly OK, IMO.



Ken, do you think that the correct placement for the Taco 0010 is on the primary loop, at about six or seven feet out from the Garn?  Can I make it closer?


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## slowzuki (Jan 21, 2009)

The pumps can be as close to the Garn as you like.  Actually the closer the better!  I can see it would be a bit cleaner to have them in the room though if need be.

RE the building inspector, its really just contact outputs that will turn each circ on or off.  All the safety controllers that he should be worried about should be built into the Garn's combustion controls.

The hot tubs and green house will likely be some type of basic thermostat, the HX circ we haven't talked much about yet but can be done a few ways off the existing system.  I'm assuming your thermostats are wired inside of walls and not really accessible. We can help you out with that, a few different approaches available.  I'll try to get a chance to relook at the diagram today.


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## Jim K in PA (Jan 21, 2009)

slowzuki said:
			
		

> The pumps can be as close to the Garn as you like.  Actually the closer the better!  I can see it would be a bit cleaner to have them in the room though if need be.



As long as it is nice and low, close to the floor.



> RE the building inspector, its really just contact outputs that will turn each circ on or off.  All the safety controllers that he should be worried about should be built into the Garn's combustion controls.



The GARN is an unpressurized system, and has few "safety" controls.  There is a low water cutoff that disables the draft fan, an on/off switch, and a mechanical timer that controls the run time of the draft fan.  That's it.



> The hot tubs and green house will likely be some type of basic thermostat, the HX circ we haven't talked much about yet but can be done a few ways off the existing system.  I'm assuming your thermostats are wired inside of walls and not really accessible. We can help you out with that, a few different approaches available.  I'll try to get a chance to relook at the diagram today.



He'll need another water:water HX for the hot tub.  Something small and compatible with his treatment chemicals.  He can probably use the temp controller from the hot tub that currently actuates the relay for the resistance heater, and use that signal to start the circ pump for the loop.  If he wants to have the radiator on this loop to run independant of the hot tub, then a second controller and pump will be needed.


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## slowzuki (Jan 21, 2009)

Really, the Garn doesn't have a high temp cut out for the fan?  What stops you from boiling it over?


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## Jim K in PA (Jan 21, 2009)

slowzuki said:
			
		

> Really, the Garn doesn't have a high temp cut out for the fan?  What stops you from boiling it over?



Correct.  YOU are what prevents a boil over.  I was also concerned about this before I started using my GARN.  To actuallly get to a boil over, you REALLY have to try, or be VERY inattentive to it's condition.  Here is a link to my thread about this very point: https://www.hearth.com/econtent/index.php/forums/viewthread/29420/

After living with it now for 6 weeks, and having my teenage sons running it for a couple of weeks when I could not, I have to say that boil over risk is very low.


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## slowzuki (Jan 21, 2009)

I'd say our local inspector would make you wire a high temp cutoff aquastat into the fan controls.  Just strikes me that if you were to boil it over it has the power to make a lot of steam.  Do you plumb a vent through the roof?


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## Jim K in PA (Jan 21, 2009)

slowzuki said:
			
		

> I'd say our local inspector would make you wire a high temp cutoff aquastat into the fan controls.  Just strikes me that if you were to boil it over it has the power to make a lot of steam.  Do you plumb a vent through the roof?



The manway is "sealed" with a gravity set lid and gasket, and there is a vent pipe that goes from the upper manway down through the tank and out the front wall.  That will let you see if there is steam emanating due to over-firing BEFORE there is a boil over.  Given the substantial thermal mass of over 1800 gallons (or 1400 gallons in Robert's situation) there is a much more gradual buildup toward boil-over than with a unit that is only heating 10, or 50 or 100 gallons of water.

If you go through the other thread, you will see that there are consequences of shutting down the draft fan with a full burn going.  The risks associated with a boil over are primarily water and (unpressurized) steam release.  Messy, but no danger to life, limb or property.


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## slowzuki (Jan 21, 2009)

I've not read of the risks, my Jetstream simply turns off the induced and forced draft fan when it overheats.  You may get a bang from a back puff.


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## rvtgr8 (Jan 22, 2009)

I have a question about the HX size.  I had an engineer friend do the heat loss calculations on the house including the garage not too long ago and he gave me a 43,000 btu figure.  This was before my indoor storm windows and the garage was supposed to be a garage.  He designs radiant systems and has a good reputation, so I don't think he is too far off.  My question is that if I am going to run my greenhouse off the Garn side of the system, is a 90 plate or even an 80 plate overkill?  I am not sure I am using some of the suggested sizing software correctly, but it looks like a 50 or a 60 are more than adequate.  I plead ignorance.  Any suggestions?


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## Rick Stanley (Jan 22, 2009)

Hi Robert,

Take what I say with a grain of salt as I'm still trying to figure my own system out. The pro's in here will give you some solid answers as always. But it's my understanding

that the only reason I need a hx at all is to interface with my existing pressurized boiler and distribution system. 

Any loads that don't exist yet, like a greenhouse, may not need a hx.  Just pump Garn heated water directly through the new distribution system.

Just a thought.

Rick


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## slowzuki (Jan 22, 2009)

How are you heating the green house?  Rick is likely right.


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## Jim K in PA (Jan 22, 2009)

rvtgr8 said:
			
		

> I have a question about the HX size.  I had an engineer friend do the heat loss calculations on the house including the garage not too long ago and he gave me a 43,000 btu figure.  This was before my indoor storm windows and the garage was supposed to be a garage.  He designs radiant systems and has a good reputation, so I don't think he is too far off.



That is an impressively low number for your area.  What was the design max delta T?  Had to be about 80 (70 inside, -10 outside) at least.



> My question is that if I am going to run my greenhouse off the Garn side of the system, is a 90 plate or even an 80 plate overkill?



Are you saying that you will supply heat to the GH directly rather than through the HX?  There is no reason why not.



> I am not sure I am using some of the suggested sizing software correctly, but it looks like a 50 or a 60 are more than adequate.  I plead ignorance.  Any suggestions?



As I understand it, there are two primary factors in sizing the HX.  One is the AVERAGE maximum load, the other is the maximum PEAK load.  Secondary factors are efficiency of transfer as the load and supply temps get closer, and the amount of head loss through the HX.

The peak load issue is something I discovered after letting a radiant heat guy size my HX.  He convinced me that a 20 plate HX was more than adequate for my calculated 70k Btuh house load.  The HX does actually keep the zones warm at max load (we just went through below 0 temps), while the zones are running.  However, PEAK load, when cold zones start up, and/or when there is a prolonged hot water demand (Showers) the oil burner kicks on to keep the temps up.  

Consider that a shower is roughly equivalent to a heat load of over 112k Btuh (3 gal./min, delta T of 75). And when a zone kicks on after a period of inactivity, the return temp is near ambient, so you have a big Delta T on each zone to catch up with.  If multiple zones hit the HX simultaneously that way, well, lets just say that the HX will be taxed.  

I am upgrading my HX to a 50 plate for the peak load capacity, and to reduce the head loss through the HX.  Without the hot tub and GH pulling heat through it, I think the 50 plate will be quite adequate.


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## rvtgr8 (Jan 22, 2009)

The Greenhouse will be built this year, and while I would like to run some heating tubes in some of my beds, the idea is not to heat the entire space.  There are problems that I will deal with to even do the most modest of system.  I do not have the luxury of having soil between here and the greenhouse, its situated on the lee side of a sandstone escarpment.  Not impossible to get through, but if the cost of running a loop exceeds the cost of a smaller boiler dedicated to just the greenhouse...well that's a situation a couple of years down the road. Truth be told, besides the new hot tub and radiator, the 43,000 btu figure is pretty solid on that side of the HX.  The HX does not have anything to do with any of the future plans for now.

Robert


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## TCaldwell (Jan 23, 2009)

robert, i have a historical heat load that fluctuates from 55k to 65kbtu/hr weather dependant , consisting of 7 zones however as jim states momentary heatloads of 3 plus zones at the same time  and it temporarily jumps to 300k+btu/hr, you want to try to cover these demands even with a low supply temp, maximizing your storage. most hx manufacturers will help you through proper sizing, based on heat load, supply temp range, flow rate and desired delta t.


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## slowzuki (Jan 23, 2009)

The other way to deal with peak loads is to put something like an 80 gal tank into the hose loop but I'd much rather keep a large hx and reap the benefits of being able to drain the Garn down to low temps so you can go longer between firings.


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## rvtgr8 (Jan 23, 2009)

Thanks for the input guys.  It gets a little easier to understand every day.  On another note, the inspector wanted to know if there was any problem using a HX and then circulating the water through the Burnham boiler on the old loop.  I explained that I it would not.  The only difference between the way it is hooked up now and the way it would be hooked up after the Garn is hooked into the system is that it would be like the temps in the old loop stayed warm perpetually, never dropping low enough to fire the propane in the boiler unit.  He wanted to know about the possibility of a mixing circulator at some point.  I talked to him about that possibility based on the information I have received in this thread, and he liked that.  I hope I was correct in my explanation.  He really wanted a little more detail.  Any suggestions?

Robert


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## rvtgr8 (Jan 23, 2009)

Slowzuki,

I see your point and will be going with the larger HX.  Thanks for your valued opinion


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## slowzuki (Jan 23, 2009)

Hi Robert, I don't know what kind of relationship you have with your inspector, I don't know why he wants so much info but its best to keep him happy.

My opinion is the current radiant setup without the mixing circulator may not be the best but it works well for you from all reports.  I would be hard pressed to start messing with it although some type of mixing may eventually be needed for when the Garn is at its highest temperature.  This could be avoided by a variable speed circulator on the Garn HX or a 3 way/4 way mixing or injection setup on the house side.

The problem a mixing device can solve is the water being too hot causing the temperature in the slab to swing too high overheating the occupants.  If you don't have a problem it won't help you other than in some cases you may be able squeeze a bit more useful heat out of a storage tank.

By using a VS pump on the Garn side of the HX, you can just put a temp sensor at the discharge side of the house side of the HX so the Garn will only run the pump enough to maintain the temp.  Once it falls below the target temp it will run the pump faster and faster until it is at 100% speed.  Fancy variations of this include "outdoor reset control" which would change the house temp setting based on outdoor temp. This is really the exact same as injection mixing just through a HX.


EDIT and looking around they seem to be really expensive.  I'll keep looking to see if there is a cheap one I missed.  Kind of silly, VS drives are dirt cheap now.


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## rvtgr8 (Jan 24, 2009)

The inspector and I go way back.  I built a straw bale hybrid (first in my county), put in a bio-peat filtration system on my septic (first in Colorado) and then ran for commissioner.  Nice guy, but he looks at me as some sort of a dreamer/schemer.  He is just curious, but I do have to stay on his good side.  I have more weirdness planned here at the ranch. :cheese: 

Would the Grundfos UPS 43-44FC that Jim K is using be a good VS circulator for the primary loop on the Garn with the 2" pipes.  There is not a lot of head loss in my system yet.  Who knows what the future hold?  But for right now, I want to start narrowing in on some concrete solutions for pricing purposes.

Robert


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## Jim K in PA (Jan 25, 2009)

rvtgr8 said:
			
		

> Would the Grundfos UPS 43-44FC that Jim K is using be a good VS circulator for the primary loop on the Garn with the 2" pipes.  There is not a lot of head loss in my system yet.  Who knows what the future hold?  But for right now, I want to start narrowing in on some concrete solutions for pricing purposes.
> 
> Robert



Th Grundfos is a 3-speed PSC pump, not a variable speed.  You can control it with a differential setpoint VS controller like the TEKMAR 157, or 356, or . . . ?

I thought you already bought those TACO 0014s?


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## rvtgr8 (Jan 25, 2009)

Jim,

No, the guy still has them at the same price ($200 for two Taco 0010's) but I was not picking up the vibe that it was not the pump that would do the trick.  Do you know of a good three speed that I can run on the primary loop and perhaps run on an outside reset? 

Robert


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## rvtgr8 (Jan 26, 2009)

I now find myself mired in the "which pump" zone.  Its a confusing place filled with red, green, pink and black devices.  They come with charts and numbers and wires and mighty flanges.  I am humbled.  I know that I am a reasonably intelligent human being, able to do math without assistance from fingers and toes, but I lack any tangible experience in hydronics.  I spent countless hours perusing data sheets on circulators this weekend.  I read and reread any posts that have a Garn installation discussion.  I have come to the conclusion that this process takes a great deal of  "hunch" decision making.  I am trying to decide between a three speed Taco 0010 or a comparable Grundfos UPS 43-44FC/BFC SUPERBRUTE. Hands down Grundfos has the Taco beat in terms of cool names.  The red paint looks good.  But the Taco has that cool green that goes with the ugly paint on my garn.  Never mind that the literature has the two rated as a toss up. 

Long story short!  How do you guys make these decisions?  Cost? Availability? Color scheme? Coin flip? Ground hog?

Help!

Robert


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## slowzuki (Jan 26, 2009)

Hi Robert! There is some madness to pump selection.  For your main circulator feeding the HX the following would apply.

1) Find out how many gpm we need on the HX to obtain the desired performance.
2) Figure out pressure drop in HX and system piping at the gpm picked in step 1 from the circulator to HX back to tank.
3) Look at pump curves, mark a point showing the gpm and ft of pressure drop.
4) Curves above this point will provide adequate performance, but, eliminate any pumps that are at the extremes of their curves ie you don't want to be running a monster pump at near stall conditions or making pump run out to the extreme limits of its capacity.
5) If you still have several pumps left at this point, check the power use and efficiency and go for the least power/most efficient.

The hardest thing is finding the pressure drop.  You will need to use a Hazen-Williams headloss calculator.  There are online ones.  You also need to have pipe measurements and fitting counts.

For common pump sizes there will be models available from each brand.  Do you like chevy or ford basically at that point!


OH, if you want to implement an outdoor reset mixing type setup right from the start using the HX pump, you will need a VS pump.  That will reduce your selection of available pumps.


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## rvtgr8 (Jan 27, 2009)

Okay, this is the latest drawing done to help me figure out pipe sizes, fittings and flow rate.  I am having little luck figuring the correct heat exchanger size.  Using rudimentary figures and GEA software, I keep finding a HX much smaller than the ones I have been talking to members about.  Quite frankly, I do not know what I am doing because the software is pretty straight forward, so I must be plugging in the wrong numbers.  There is a hell of a lot of difference between the twenty plate that it is telling me to consider and the 70 plate that I thought I needed.

The drawing is a little funky in that it shows that I am going to put the circulator on the primary loop outside of the boiler.  That is correct.  I just do not have the room inside the boiler room to put both the manifold and the exchanger.  It is a plus in that it rids me of a couple of elbows.  Any thoughts?


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## Jim K in PA (Jan 27, 2009)

Robert,

The way you have shown it, the pump is in the wrong place, IMO.  You are not building an primary/secondary piping system, based on this drawing.  You are showing a manifold system.  Given the size of the load on the house loop, I would use a dedicated pump for that loop, as well as all the other loops.  They can be sized according to each load, and controlled independantly.

Your piping losses are going to be minimal, given the small amount of pipe you are showing.  The HX will be the single biggest component of head loss on the house loop.  For my house loop, with over 250' total piping distance, plus an undersized HX (20 plate), my Grundfos UPS 26-99 is more than adequate.  It is a high head, medium flow pump, smaller than the 43-44.  I have it set on medium 24/7 right now, but will be adding a variable speed controller to it, as it can often run much slower than it does (but sometimes needs to pump faster under higher loads).

At the moment GEA wont let me log into the sizing software.  However, the closer you make the target output temp to the input temp, the bigger the HX will get.  As I described previously, my 20 plate HX is actually working fine - at average loads.  With peak loads, my delta Ts get extreme, and increasing the pumping rate results in greater head loss (more resistance).  Also, as the GARN water cools, I cannot get as much heat out of the small HX as is available.  That is, if my GARN input temp is 150, I can't get much more than about 140-142 out of the HX.  My oil furnace cut in is set at 140, so that is when it starts to fire to supplement the GARN (and I HATE burning oil!).  With a bigger HX, I should be able to let the supply temps dip below 150 and still keep the house side above 140.

Personally?  I think you should plumb the supply side out to the utility room in 2" pipe and branch off the manifold with 1.5" for the greenhouse loop, 1.25" for the house loop, and 1" for the hot tub loop.  Put a 26-99 on the house loop, and a 15-58 on the hot tub loop.  Greenhouse pump to be determined later.  Use a 50 plate HX for the house loop and a 20 plate for the hot tub loop.  Greenhouse can be in series, or use a seperate 90 plate HX.


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## rvtgr8 (Jan 30, 2009)

Jim,

Is this what you were referring to, with these pumps?  Would a Tekmar 356 be a good control for this setup?

Robert


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## timerak (Jan 30, 2009)

I use  a Tekmar 356 on my heat exchanger feed pump. Its the ticket if your doing radiant. It's controlled by the mix temp on the house side of the heat ex. (mix temp is set by outdoor sensor) Mix temp stays constant wheather storage temp is 180 F or 120 F. I think I paid about $255 locally. It was the cheapest way to do what I required. 
Tim....


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## Jim K in PA (Jan 30, 2009)

Robert - yes, that is the configuration I was suggesting.  With manifolds, you only need to pull/push water through the legs that need it, so you don't need a "primary" pump.  As long as there are check valves on the other legs or in the other pumps, you should not get reversion through the return leg.

I think the 26-99 will be plenty for the house leg, and you will likely be able to run it on low speed and still meet your demand.  The Grundfos specs put your house HX load right at the upper end of the 15-58, so going with the larger pump will reduce  it's duty cycle and let it have a longer life.

As for controls, the 356 would be something to consider for the pump on the house side of the HX (as Tim suggested above), not the GARN side.  However, I would operate your GARN side pump for a while and monitor S/R temps and see if a variable speed controller might be worthwhile.  There are pumps available from Wilo and TACO that have integral VS controllers, however, they are more expensive, and you are trying to work within a budget.  The three speed pump gives you some control at lesser cost.  You can add a Tekmar 157 later to vary the speed according to demand on the HX.  For now, just add a relay to bring the 26-99 up whenever the existing circulator comes on.


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## timerak (Jan 30, 2009)

Robert and Jim:

The last schematic I saw indicates that the secondary side of the heat ex is the secondary/mix loop. I didn't see a tempering valve/scheme anywhere else in the system. Therefore the pump on the primary side of the heat ex would be the injection pump for generating a controlled tempered mix for the radiant. It could be controlled by a 357 or 157. Is there a third loop/mixing valve/injection scheme that will do tempering that is not drawn? 

Tim....


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## Jim K in PA (Jan 30, 2009)

timerak said:
			
		

> Robert and Jim:
> 
> The last schematic I saw indicates that the secondary side of the heat ex is the secondary/mix loop. I didn't see a tempering valve/scheme anywhere else in the system. Therefore the pump on the primary side of the heat ex would be the injection pump for generating a controlled tempered mix for the radiant. It could be controlled by a 357 or 157. Is there a third loop/mixing valve/injection scheme that will do tempering that is not drawn?
> 
> Tim....



Tim - you are correct, there is no mixing valve on his radiant system at this time.  The original installer has his existing propane fired (high mass, not a mod-con) boiler ranging from 140-180 (I think - it is several pages back) with these temps running through the floor loops.  Robert also has an indirect DWH running off of one of the zones.  He will need the higher water temps for the DWH, unless he runs a seperate loop from the GARN through another small HX and supplies heat to the indirect that way (or seperates it from the radiant zones).  I was trying to help him get his GARN up and running with a limited budget, and this first stage may have to omit water tempering via pumps, controllers, or mixing valves.


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## rvtgr8 (Jan 30, 2009)

Boiler Enthusiasts,

I cannot thank you enough for your valued opinions on my project.  It is a tribute to the spirit of common cause and genuine friendliness that this site is so successful.

Jim, thanks for the clarification.

I know the house side of the system will probably need a mixing valve.  Does anyone know of one that would be sufficient for my system.  I have some cash left in my budget, and if I do not spend it on the boiler, it will probably go on something frivolous like food.   hh:   In addition, would the Tekmar 356 be a fit with the mixer?  I assume that it would, but I have been known to be pretty thick.

Robert


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## rvtgr8 (Jan 31, 2009)

I have been doing some research and was surprised to see the the Taco Iseries automated mixing valves do not go up to the 1.25" pipe size that I will need.  Is the Tekmar 712 mixer a pretty good mixing valve?  How absolutely necessary would the actuating motor for this be?  If I am out there being a heating geek and salivating all over my equipment as I anticipate, can't I just manually adjust it, or would not spending the extra $250 coupled with the fact that I will already have a Tekmar 356 controller be an insult to the Gasification spirits? :bug: 

Robert


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## slowzuki (Feb 2, 2009)

Hi Robert and Jim back on board, I'm internet free on weekends.

Robert, I'd say don't worry about the mixing valve for now.  Jim and I are both recommending using the pump that supplies the HX as the tempering device.  By using a controller or intelligent pump that watches the output of the HX on the house side, it will adjust the pump speed to hit a given temp.

This saves trying to get a mixing valve setup and is a lot simpler/reliable.  If you can't afford the variable speed pump or controller, the 3 speed pump is essentially a 3 position mixing valve.  Warm weather it runs on the slowest speed, cold its set to the fastest speed.


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## rvtgr8 (Feb 10, 2009)

Slowzuki,

Thanks for the PM.  I really appreciate your attention to my situation.  My current situation is a waiting game.  My thread on Pex Supply speaks volumes on just how important having a good source for parts can be to a project.  I do not have enough cash to double purchase every item that Pex Supply does not include in one of my orders.  I have called them.  They say they have the parts and will ship immediately.  Does the shipment arrive?  No.  Has it shipped? Apparently not or I would have a tracking number.  So I am on hold, unable to move forward. If I cancel and reorder, it can be a real hassle with my card company.  I made another mistake by not doing my homework on Pex Supply.  Lesson learned.  I will wait one more day and then cancel and reorder through a more honorable company.

When the stuff comes, or I sandcast my own, I will be in touch for your invaluable opinion on the install.  You, Jim K and others are truly the only bright spot in this rather dismal project.

Robert


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## Jim K in PA (Feb 10, 2009)

Hang in there Robert.  The momentum is building, and you will be up and running before the year is out . . .  :lol: Sorry - couldn't resist.  You may recall from my blog, I had delays every step of the way, from the delay in delivery of the GARN through the PEX tubing, pumps, PEX fittings, proprietary PEX tools, ad nauseum.  Keep the faith.


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