# Looking for pics or descriptions of how to plump 2 500 Gal. Propane Tanks together.



## churchillrow (Oct 28, 2009)

Hi, I'm getting ready to get some tanks delivered to my welder and I'm not sure what to get him to do.  I haven't decided between primary / secondary or simplest pressurized system but am leaning towards the latter if it makes a difference.

Thanks


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## stee6043 (Oct 28, 2009)

Do you have a system layout drawn up?  I'm not sure how you schedule a welder without knowing what you're going to have him weld!  Start with a sketch of your system....that's the first step....


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## churchillrow (Oct 28, 2009)

The reason I'm rushing the tanks is that I will have access to my basement by boom truck for a short window when my house is torn apart for reno's.  I don't have a system designed yet... I am waiting on heat loss calcs before I choose a boiler.  When I have them which I hope will be soon I'd like to throw the boiler and the tanks down there and figure out everything else later.  Is this a dumb approach?  Can I take from you previous reply Stee that system design would affect how the tanks are plumbed?

Thanks again


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## ulooknatme (Oct 28, 2009)

I went with 3 in the top, middle and bottom.(all 1-1/4") Only the nipples on the tanks are 1-1/4 but the manifold is 1-1/2. Works pretty good at keeping the tanks stratified all the way to the bottom. My top tank is 330 and the bottom 1000.


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## sgschwend (Oct 29, 2009)

There is no such thing as too many connections.

I am using one 500 gallon tank, here are the connections for it:
1 1/2 on left used for return, a 36" nipple is married to the bushing.  The nipple goes to the bottom of the tank, the end is plugged and 8- 1/2" holes are drilled radially,
1 1/4 bushing welded into gage hole used for the 1" boiler hot water input
1 1/4  bushing married to a 4" long nipple to be used for the pickup (any air bubbles will be above the nipple)
1/8 npt tapped for an air separator

All of my "special" parts are screwed in so they can be removed and replaced.  I did not put any connections in the bottom, my circulator pump is below the tank elevation.


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## Gooserider (Oct 29, 2009)

How many tanks, and what sizes are they?

How do you plan to install them?  Side by side?  Stacked on a rack?  Horizontal, or standing on end?

If you can figure this out, then a lot of the tank setup for fittings and such becomes fairly "standard" regardless of how the rest of the plumbing hooks up, because the tanks are pretty much doing the same thing no matter how your system is designed...

In your situation, I would say to make sure that you have it so that you can get water in the bottoms of the tanks and out the tops (or vice versa), preferably with as little turbulence and mixing as possible.  

If you are going to be stacking the tanks, put in a few pairs of connections so that you can tie them together with as short and straight a hookup as possible, ideally in several places - i.e. ports in the top of one tank and the bottom of the other.  (In effect making them one big tank)

Ideally make the ports bigger than you plan to use, as you can always bush them down, but you can't make them bigger.

If I was doing something, and had a willing welder (and possibly a large budget) I'd probably try putting a fitting in one or possibly each end of the tank near the top and bottom (If stacking near the top of the upper tank and the bottom of the lower one) that would let me run a pipe along the top and bottom of the tank interior so that I could drill a bunch of holes in it and use it as a diffuser....

Another item that could be a wonderful thing for some plumbing setups is if your tank had a "manway" style port that you could optionally use as a way to insert HX coils into the tank - something that can't be done in most cases with a pressured tank, and that is IMHO the biggest single drawback to a pressure tank...

BTW, just from a future proofing standpoint, will you still be able to get a tank in and out of the house when your renovations are finished?  Tanks should last a long time, but someday they WILL leak and need replacing...

Gooserider


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## churchillrow (Oct 29, 2009)

Lots of info.... 
Gooserider:   The 2 tanks I am using are 500 gal, 9.5 ft long and 36" in diameter so I should be able to get replacement tanks into the basement.  I would like to stack them horizontally one atop another on pallet racks or the like.  The diffuser idea seems good but if it is to expensive or impractical can I put a diffusing "nipple" into the bottom of the bottom tanks and the top of the top tank?  Can you give me an idea situations where a HX would be useful in a pressurized system?  How Big is a big port, 1.5" ??

Steve: 
"1 1/4 bushing married to a 4” long nipple to be used for the pickup (any air bubbles will be above the nipple)
1/8 npt tapped for an air separator"

Pardon my ignorance but what is the "pickup"
And what is an air separator?

Ulook:  You say you are getting good stratification.  Do you have diffusers or just nipples in the tanks.

Thanks for the pics and ideas


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## jebatty (Oct 29, 2009)

Repeat info on stratification in a horizontal tank, 39" diameter, 19' feet long, 1000 gal. Return from a diptube about 4" off the bottom, and 1/3 from one end of the tank, using an existing fitting. Supply using an existing fitting with a 90* bend inside the tank to inject hot water horizontally along the inside top of the tank in a direction opposite from the diptube, also about 1/3 form the end and about 1' from the diptube. Stratification is intense and tank heats very evenly, top to bottom. Example: top of tank may be 160F and bottom of tank (if start from "cold") easily could be 90F. Bottom of tank will stay 90F until whole tank is heated, then bottom of tank temp rises fairly rapidly as whole tank above is hot.


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## Gooserider (Oct 29, 2009)

churchillrow said:
			
		

> Lots of info....
> Gooserider:   The 2 tanks I am using are 500 gal, 9.5 ft long and 36" in diameter so I should be able to get replacement tanks into the basement.  I would like to stack them horizontally one atop another on pallet racks or the like.  The diffuser idea seems good but if it is to expensive or impractical can I put a diffusing "nipple" into the bottom of the bottom tanks and the top of the top tank?  Can you give me an idea situations where a HX would be useful in a pressurized system?  How Big is a big port, 1.5" ??


You can use a diffusing nipple, or whatever else you can make work - the basic idea is that you want to move the water in and out of the tanks with as little mixing as you can manage so as to keep as much stratification as possible.  

The idea of using an HX is pretty much any case where you need to transfer the heat to another system, and can't use the boiler water directly for whatever reason...  Possibilities might include preheating for DHW, a glycol loop to feed a garage heater, swimming pool heaters, solar systems, etc...  All of these can be handled with sidearm or flat plate exchangers, but this takes extra plumbing, and can require more pumps.  OTOH, an in tank coil is very simple and direct, adds no moving parts, or other such complications...  With a non pressurized tank, it is easy to add as many coils as one wants, but it is difficult with a pressurized tank unless one has a "manway" in which case you have some way to slide a coil into the tank and either hook it up to fittings in the tank wall, or possibly in the manway lid itself...

Big port is sort of an ambiguous term, I would probably say the simplest definition is at least 1-2 sizes bigger than the pipe you are thinking of hooking up.  Fittings and bushings get more expensive as the size goes up, but you gain in the ability to slide more things into the tank like dip tubes and diffusers, etc...  I haven't seriously priced welding stuff into tanks, but from what I've heard, the costs for the fittings to get welded into the tank are such a tiny part of the cost as to be almost irrelevant, and that there isn't a lot of difference in the welder's labor fee for a big fitting vs. a little one, as both involve about the same amount of setup and prep.  Talk to the welder, but I'd almost be inclined to go for 2-3" ports just for the flexibility.

[/quote]Steve: 
"1 1/4 bushing married to a 4” long nipple to be used for the pickup (any air bubbles will be above the nipple)
1/8 npt tapped for an air separator"

Pardon my ignorance but what is the "pickup"
And what is an air separator?

Ulook:  You say you are getting good stratification.  Do you have diffusers or just nipples in the tanks.

Thanks for the pics and ideas[/quote]
Not to speak for Steve, but my guess is that by "pickup" he is meaning the outlet for the tank, or the point where the hot water goes in and out.

An air separator can be used to refer to several different items, but generally is a vent type device used to purge air trapped in the system.

Gooserider


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## churchillrow (Oct 29, 2009)

Gooserider
  Thanks for your always thoughtful suggestions,  I am going to try to come up with what I am actually going to do and I will post here after I've talked to the welder.


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## ulooknatme (Oct 29, 2009)

Just nipples. Before putting the insulation on and having 160* water entering the tanks, you could put your hand on the side of the tank and it would be cold....move your hand up just a few inches and it would be hot. (the same distance all the way across the tank.)


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## sgschwend (Oct 29, 2009)

Yes, the 4" nipple means that the water that leave the tank/reservoir comes from just below the top of the tank, keeps the trapped air or floating junk from getting sent to the loads.  This is a very important part and it makes getting the system up and running possible.  Without it the first large bubble that reaches the pick-up will move to the circulation pump and stop the pumping.

The air separator (sometimes called an air vent is a TACO 400-3) has a cap that you open to allow it to operate.  Air can exit through the cap but as the water rises in the device it will push a float up and close the valve inside, hence trapped air is bled out but not the water.

I have two married parts which are 1" diameter nipples welded to bushings.  The bushing threads into the tank.  The four inch is a pickup, the 36" is a return.  The 8 -1/2 holds drilled radially exceeds the area of the 1" pipe (the pipe end is closed so that all of the water is sent horizontally to minimize agitation.  My loads are low so my flow rate is not that high.

The other tank pics had three boiler to storage tank input ports that might be nice to have.


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## RobC (Oct 30, 2009)

Any pipe that needed to be welded in place I used heavy wall or schedule 80. This doesn't include the 1/2" black used for sensors. On upper tank the 2" nipple just goes in and is flush with top of tank and makes a 90 and reduces to 1.5". The bottom nipple is 36" X 2" and goes almost to bottom of tank. I welded a piece of flat stock to the end of this to act as a diffuser so water is pushed to bottom of tank. The way that pipe goes into tank it's at an odd angle, it looked like the incoming water would push up the side of the tank causing mixing. I used a dip tube on the side for easier access for threading and to keep pipe off the floor, but the pipe is inside the sides of the 2 tanks, out of harms way. I add a support frame after tanks were slid into place for extra stability, and to take some of the weight off the legs of the lower tank. After the tanks are insulated the frame will give me a place to attach some sheet rock / fire retardant material. I have had success with a 100G propane tank for the expansion tank for the system.


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## jebatty (Oct 30, 2009)

Something that is worth considering in any hydronic install is a hot water filter on the hot water line leaving storage and supplying the system; also on the boiler return line. I use a 50 micron filter on mine, although I just picked up a case of 100 micron filters off of ebay at a buck a piece. Besides filtering any crap in the lines, when you change the filter you get a pretty accurate read of your water condition from the color of the filter. Any brown or reddish color indicates rust/corrosion somewhere and likely indicates you need an increase in alkalinity.


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## churchillrow (Oct 30, 2009)

Steve-- Smart with the air stuff.

Rob -- I take it that your 1/2" sensor pipe is welded on to the surface.  Also I didn't follow about the dip tube....  I think I am going to try to find used pallet racking to hold the tanks as I have no welding skills.

Jim -- Filters sound good....  

 Interesting how many little details people come up with to refine their installs.  Maybe when this thread seems dead I'll compile them all and make one last post,

Thanks Again


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## RobC (Oct 30, 2009)

The idea of diffusers or in my case a 2" pipe and a flap is to slow down the water movement into / out of tanks to prevent the mixing of the water inside the tank. You want to increase stratification by reducing turbulence. Hot water in and out on top and cooler water in and out the bottom. I knew where I wanted to put in my lower dip tube but when I slid the pipe in the hole, in the tank, I saw there was a problem. I wasn't coming in at 90 degrees and the water was going to shoot up the side and start the water in the tank spinning, reducing stratification. Another fix would have been to drill holes in the side of the pipe and cap the end. Or you could weld right to bottom of tank.
Yes, I welded the 1/2 in black to the sides. They seem to work nicely with rapid temp changes. I'm going to cut them back closer to the tanks once the insulation is on.
My side supports were to achieve a couple of things. My tanks are in a high traffic area. 
They are for added stability. 
To add support to the lower tanks legs. 
You are now asking those legs to support more than 2X what they were use to. I don't know what they are rated for nor do I want to find out. 
I also added some supports, short legs between tanks. I wanted to keep any weight off the 4" welded pipe tank connectors.
You mentioned pallet racks. Check the ratings. Don't know where your located but there is a place in Walpole, MA that sells them used. 
Rob


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## rkusek (Oct 30, 2009)

jebatty said:
			
		

> Repeat info on stratification in a horizontal tank, 39" diameter, 19' feet long, 1000 gal. Return from a diptube about 4" off the bottom, and 1/3 from one end of the tank, using an existing fitting. Supply using an existing fitting with a 90* bend inside the tank to inject hot water horizontally along the inside top of the tank in a direction opposite from the diptube, also about 1/3 form the end and about 1' from the diptube. Stratification is intense and tank heats very evenly, top to bottom. Example: top of tank may be 160F and bottom of tank (if start from "cold") easily could be 90F. Bottom of tank will stay 90F until whole tank is heated, then bottom of tank temp rises fairly rapidly as whole tank above is hot.



Jim, it sounds like you are using plain pipe (no diffusing with holes, etc.)?

Is anyone using a primary/secondary with pressurized storage.  I like the concept but I don't see how the storage could operate with only 1 circ & loop back to the primary.  Steve J  asks the question in the P/S sticky but the answer he gets suggests that it is not necessary since the tank will be mixed together anytime the boiler is producing heat.  Everyone in this thread seems to indicate the tank staying stratified while boiler is operating either with diffusing holes or locating "pickup" and "returns" properly.  I would think you could use 1 circ & 1 loop if you added 2 3way valves near the circ to reverse the direction of flow but I have not seen that discussed anywhere.  The cost of 2 3way valve is probably about the same as adding a 2nd circ with a loop I suppose.  The "switchover" process would probably overly complicate things as well.  Those with P/S how is your storage plumbed?



			
				SteveJ said:
			
		

> So, there should be two circuits into the butffer tank:
> 
> 1. As drawn in the diagram, to charge the tank from the primary loop.
> 2. (Not shown in diagram) Circulator reversed from that in diagram with a short dip tube, to extract heat from the tank to the primary loop.
> ...





			
				master of sparks said:
			
		

> Sure, you could have two loops into the buffer.  What I find is any time my boiler exceeds 150 the buffer circ is running.  As such the tank is always blended, not much stratification with the buffer tank circ running.
> 
> On one hand I want the cooler water from the bottom of the tank to return to the primary loop and boiler to leverage delta t to the boiler and keep the efficiency up.
> 
> ...


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## Donl (Oct 30, 2009)

huskers said:
			
		

> I would think you could use 1 circ & 1 loop if you added 2 3way valves near the circ to reverse the direction of flow but I have not seen that discussed anywhere.  The cost of 2 3way valve is probably about the same as adding a 2nd circ with a loop I suppose.  The "switchover" process would probably overly complicate things as well.  Those with P/S how is your storage plumbed?




Thus diagram shows the use of a 4-way valve to provide correct flow direction to and from storage.


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## rkusek (Oct 30, 2009)

Don L, what is the box above the storage circ do?  I can't quite make out what the name says.  You have three separate physical locations to deal with.


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## jason elmer (Oct 30, 2009)

Has anyone considered using a drive well point as a diffuser?


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## Donl (Oct 30, 2009)

huskers said:
			
		

> Don L, what is the box above the storage circ do?  I can't quite make out what the name says.  You have three separate physical locations to deal with.




It is a controller for the pump to move water in and out of the storage tank. It is made by Steca.  The controller has two senors. One monitors tank temperature and the other monitors available supple temperature. Basically if supply temperature is greater than tank temperature the pump will be activated. The Steca controller is normally used in a Solar application. I will be building a NFCS  controller in the near future and it will be used to replace the Steca.

Yes I have three different locations to deal with. It makes the project more complex and challenging. Also more fun.


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## ManiacPD (Oct 30, 2009)

This is great!  I have one 250 gallon tank for this year that I'm hooking up next week and plan to add a second on top of it next year.  I love this site!


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## kabbott (Oct 30, 2009)

Highjack alert.

Wow.... No wonder you need an NFCS Don! I thought I had a lot of pumps. :cheese: 
That is a nice looking diagram, do you mind if I ask what you used to create it?

Kris


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## Donl (Oct 30, 2009)

kabbott said:
			
		

> Highjack alert.
> 
> Wow.... No wonder you need an NFCS Don! I thought I had a lot of pumps. :cheese:
> That is a nice looking diagram, do you mind if I ask what you used to create it?
> ...



I use Visio for the drawings. 

Yes there are a lot of pumps, but  they are all 007 or 15-58 so they use little power. Right now I use several NoFossil inspired 12 volt relay boxes to control the pumps. The relay boxes are currently controlled by a series of relays, thermostats and aquastats that form the brains of the system.  I surprised myself on how will it is working.  The NFCS will be the icing on the cake so to speak. With it I intend to replace the Steca controller and the Techmar controller used for cold water protection, plus allowing me to really fine tune the overall system. This stuff is terribly addictive. NoFossil should put out a warning on his web site!


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## Gooserider (Oct 31, 2009)

Don L said:
			
		

> huskers said:
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Very nice diagram Don, the only thing I might suggest on it is that it looks to me like it would be better if you pulled the heat for the storage tanks off before the heat for the floor...  I would think that even though the floor might only pull a small amount of water, it is going to return cooler, and thus cool the water in the line going to the storage tanks...  If you pulled the tank water off first, you'd be getting the hottest possible water into the tank, and could use the cooler water in the floor, which has a lower temp requirement anyway...

Gooserider


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## Donl (Oct 31, 2009)

Gooserider said:
			
		

> Very nice diagram Don, the only thing I might suggest on it is that it looks to me like it would be better if you pulled the heat for the storage tanks off before the heat for the floor...  I would think that even though the floor might only pull a small amount of water, it is going to return cooler, and thus cool the water in the line going to the storage tanks...  If you pulled the tank water off first, you'd be getting the hottest possible water into the tank, and could use the cooler water in the floor, which has a lower temp requirement anyway...
> 
> Gooserider




That's not how it works. 

During recovery the pump to to the radiant slab does not run. Therefore only heat from the storage tanks is recovered. Heat stored in the concrete slab is  released slowly only into the shop via radiation from concrete to air. Once the slab is heated to max it can keep the shop relativley warm for quite a long time. The storage tanks are just required to heat the house. It would have been better to locate the storage tanks in the house basement, however my wife had something to say about that.


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## stee6043 (Oct 31, 2009)

At the risk of getting back on topic, here are a few photos of how I setup my two 500 gallon tanks.  They are plumbed in series and my heat loads are plumbed "before" the tanks so they get heat first...

And for those who are really paying attention...yes....the taco pumps in these photos are mounted in the wrong orientation...for placement only!


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## rkusek (Oct 31, 2009)

Don L said:
			
		

> huskers said:
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> 
> 
> ...



How much did that 4 way valve cost?  I came up empty on a quick search of Google and ebay.  Yours must be at least 1" if not 1 1/4" or 1 1/2".  Everything I found was small and refridgerant type.  Could not find anything that large.  It might more cost effective for me to use another circ, a few check valves, and some extra black iron pipe.  I could probably use the same "pickup" and "return" in my tank just wire circs so only 1 could run at a time.

Don, does your Loop E & B circs (house primary & woodshop primary) run 24/7?  I was wondering where to locate my large expansion tank.  This link (by Holohan) indicates the primary loop is the proper place for the compression tank, system fill, and air separator.  I would proably keep my small expansion tank and air separator above the boiler.  I am a little concerned that the flow control valves on the circs (as well as any check valves I may add) would not properly equalize the pressure at the storage tank in all situations especially when that circ is not running.  Don, this article also suggests that check valves on both sides of the secondary may be a good idea, I know you were addressing a "ghost flow" problem in another thread.

Does anyone see any problem with location of the fill valve, air separator, or expansion tanks.  My initial thought was to fill at boiler only and locate the large expansion tank right at the 1000 gal storage tank.  I'm guessing Holohan knows what he is talking about but it seems everyone here that posts their schematic has something different.  I need to get my schematic on here for review before I plumb anything I guess.


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## Gooserider (Oct 31, 2009)

Don L said:
			
		

> Gooserider said:
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I wasn't thinking so much in terms of the recovery cycle, as I was in terms of charging the tank - I would want to have the tank charged to the highest temps possible, which means I would want the hottest water going to the tank during the charge cycle, and then heat the floor with what comes out of the tank...  Right now it looks to me like during charge, the floor gets first shot at the hottest water, which means the tank gets something a little cooler (how much cooler depends on the amount the floor pulls out at a time)  However if the floor gets up to temp and shuts off before the boiler burns out, it probably doesn't matter all that much.

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

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it.  It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time...  According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging...  It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider


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## kabbott (Oct 31, 2009)

I use a variant of the back to back pumps. The problem is I have a thermosiphen issue not all the time but when it starts it goes on
for a long time. Think hard about how you layout the plumbing if you go this route. I am not sure how I will solve this yet, A single zone valve
that opens when the pumps turn on will do the trick.parallel flow checks facing opposite directions should work as well.

4-way is not an option in my case, I need the flow reversed at my hyd separator as well as the heat ex. coil.


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## rkusek (Oct 31, 2009)

Gooserider said:
			
		

> On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it.  It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time...  According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging...  It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.
> 
> Gooserider



Thanks for the tip, I will search for that link.  I was so focused on the pumps with the inline check valves, my mind didn't consider that option.  So when boiler is hot the tank will be charging, when the boiler circ is off (ie. boiler less than 140*) and the temp at top of storage is adequate (probably 120* or greater) I could extract from the tank.  When both of these are too cool then nothing will run and no reason to care about unwanted ghost flows.  The key would be that the house loads would get first crack at the boiler water in the primary loop, then the barn's unit heaters, and finally storage.  

I was going to use my 700' of 1.5 underground pex between home and barn as my primary loop but sending the hotest water from the boiler to the house first via pex makes me wonder if that is a good idea in the case of an overheat situation.  I would not want to have to replace the underground pex!   Plumbing to storage first would alleviate some of this concern, but probably give me cooler water at the water to air HX in the plenum when boiler is running.  Question is how much cooler would it be.  Unless I misunderstood, Heaterman did not see a problem with the "large" primary loop when we talked about it.  Don L's system uses a small primary loop driving 2 more "primarys" but he has 3 locations to deal with.  I could add a small primary loop in the barn and have another "primary" in the home similar to Don's but not sure if that is necessary.  Anyone have thoughts on this?  The basement of the home is located about 15 feet in elevation above the boiler and storage.  This shouldn't affect pumping on a pressurized system but I wondered about expansion tank and air separator locations.  I just want to do it right the first time.


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## rkusek (Oct 31, 2009)

kabbott said:
			
		

> I use a variant of the back to back pumps. The problem is I have a thermosiphen issue not all the time but when it starts it goes on
> for a long time. Think hard about how you layout the plumbing if you go this route. I am not sure how I will solve this yet, A single zone valve
> that opens when the pumps turn on will do the trick.parallel flow checks facing opposite directions should work as well.
> 
> 4-way is not an option in my case, I need the flow reversed at my hyd separator as well as the heat ex. coil.



Haven't looked at a zone valve, does it have a set of contacts that close when the valve is opened.  You would want to energize both this valve and the circ simulataneously.  Can you explain how the parallel checks would work?


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## Donl (Oct 31, 2009)

Gooserider said:
			
		

> I wasn't thinking so much in terms of the recovery cycle, as I was in terms of charging the tank - I would want to have the tank charged to the highest temps possible, which means I would want the hottest water going to the tank during the charge cycle, and then heat the floor with what comes out of the tank...  Right now it looks to me like during charge, the floor gets first shot at the hottest water, which means the tank gets something a little cooler (how much cooler depends on the amount the floor pulls out at a time)  However if the floor gets up to temp and shuts off before the boiler burns out, it probably doesn't matter all that much.



I felt heating loads  should get first priority. But in this case what you say makes good sense because the radiant floor loop does not require much heat. I set the mixing valve for just over 100F on that loop.  Therefore that loop could easily make use of the cooler water coming off the storage tanks.  I don't think this would be true in the case of a water/air HX in a plenum. It should get the hottest water before storage in my opinion.  I will make the changes as you suggest above.

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


> On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it.  It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time...  According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging...  It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.
> 
> Gooserider




I think you are correct on this. I did this design prior to the discussion you are referring to.  It works well so no need to make any changes. Besides I think Kabbot thinks I have enough pumps already.


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## Gooserider (Oct 31, 2009)

huskers said:
			
		

> Gooserider said:
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> 
> ...



What I've heard of being done in some cases is to use the storage tank as a sort of giant sized hydraulic separator...  Put a pipe at the top and bottom of each end of the tank (once plumbed together, stacked tanks can be considered as one big tank...) and pump hot in the top at one end, using the boiler pump and pull it out at the other with the house loop pump...  If the house is pulling as many BTU's as the boiler is making, the water essentially goes straight across the top of the tank w/ minimal mixing.  If the house is pulling less, the surplus automatically charges the tank.  You could do the same thing with a big tee fitting at the top and bottom, but IMHO flowing through the tank might be better....  Essentially what this does is separate the house and other loads from the boiler - all the loads or the boiler sees is the tank.  Aside from possibly taking a little longer to get heat when doing a total cold start, I think this is a really good way to deal with pressurized storage, as the tank gets the hottest water, but simply passes it on to the load when needed.  You can then do copper or black iron between the tank and boiler, and pex from the tank outlets on.  It also means that the loop from the boiler to storage should be short and low head so that one could use a small pump  (I'd look at one of the temp responsive ECM pumps as that would allow ultra simple return protection as well)...  Since the house loop then no longer has to deal with pumping through the boiler, (and the storage tank has virtually zero flow resistance) it might also be possible to downsize the house pump (and again look at some sort of speed control on that pump)

What I would do for expansion and air venting is put the main expansion tanks on the hot side boiler - storage loop, along with an air / dirt separator.  I would put a second separator and possibly a small expansion tank at the highest point on the house loop.  (The house loop could easily be a second PS loop or hydraulic separator setup depending on the nature of the house loads - but that is a totally separate design from the boiler / storage setup - essentially design it assuming you have a hot water supply and return pipe coming from "you care not where" and build around that...)

Gooserider


Gooserider


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## kabbott (Oct 31, 2009)

Gooserider said:
			
		

> huskers said:
> 
> 
> 
> ...



That is the "hot" setup in my mind right now, although the "best setup" seems to change month to month with me as I learn new ideas.
Use the tank as the separator and if you have multiple pumps for loads you can use one tap on the tank and a manifold or multiple taps, one
for each pump.

Same on the charge side if you have more than one boiler. For fossil fuel boiler you can tie into the load side manifold so it will not heat the storage.

I'm sold...... now if I could only get a big tank in my basement!


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## Gooserider (Nov 1, 2009)

kabbott said:
			
		

> (much snipped)
> 
> I'm sold...... now if I could only get a big tank in my basement!



I agree...  Same problem here, it will be tough enough just getting a boiler into the basement, no way I could get any sort of pressurized tanks in...  I'm going to have to do non-pressurized storage, which looks like it would be a lot easier, but has a different set of issues to deal with...

Gooserider


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## rkusek (Nov 2, 2009)

Thanks for feedback Goose & Kabbot.  I had not read about this option yet.  I think I will start a new thread on this.


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## Medman (Nov 20, 2009)

Jim, how is the top fitting with the 90* bend physically accomplished? Copper or black pipe?


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## DenaliChuck (Nov 20, 2009)

My plumbing schematic is based on Bioheat USA's plans.  However, instead of their tanks, I have two 500 gallon propane tanks on their sides and next to each other.

I plumbed from the boiler to one end of the top of tank 1 using a 6" long by 3" diameter dip tube.  This lays the hottest water gently on the top of the tank.  From the other end I installed a 36" long x 3" dip tube that delivers cooler water into the top of one end of tank 2 using a 6" long by 3" diameter dip tube.  From the other end of tank 2 I installed a 36" long x 3" dip tube that returns the coolest water to the boiler.

My 1-1/4 inch copper is plumbed into the 3" pipe and there doesn't seem to be much turbulence/mixing as I get stratification of about 25-35 degrees routinely.


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## chuck172 (Nov 20, 2009)

I get about a 25-40* stratification with my 500 gallon tank. Is this about the norm?


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## Grapenut (Jan 1, 2011)

RobC said:
			
		

> Any pipe that needed to be welded in place I used heavy wall or schedule 80. This doesn't include the 1/2" black used for sensors. On upper tank the 2" nipple just goes in and is flush with top of tank and makes a 90 and reduces to 1.5". The bottom nipple is 36" X 2" and goes almost to bottom of tank. I welded a piece of flat stock to the end of this to act as a diffuser so water is pushed to bottom of tank. The way that pipe goes into tank it's at an odd angle, it looked like the incoming water would push up the side of the tank causing mixing. I used a dip tube on the side for easier access for threading and to keep pipe off the floor, but the pipe is inside the sides of the 2 tanks, out of harms way. I add a support frame after tanks were slid into place for extra stability, and to take some of the weight off the legs of the lower tank. After the tanks are insulated the frame will give me a place to attach some sheet rock / fire retardant material. I have had success with a 100G propane tank for the expansion tank for the system.



Rob,

Can you tell me more on the 1/2" black pipes you welded to the side of your tanks for your temperature sensors?

Thanks,
Rob


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## RobC (Jan 2, 2011)

They are just regular 1/2" black pipe tacked on to tank. I used them to slide in digital temp probes. I separated the tanks into quarters and added an extra one close to the top. I used this setup so I could insulate over the top or close off tanks behind wall but still have access to temp sensors with out taking everything apart.


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## Grapenut (Jan 2, 2011)

Rob,

How did that setup work for you?  Do you feel you get precise readings without actually having the thermowells inserted into the tanks?  Is your data useful for verifying stratification?  What brand and model thermometers did you wind up purchasing?  Would you do anything different if you were going set them up again?

Rob


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## RobC (Jan 2, 2011)

These are the thermometers that I used. I also use a solar controller on boiler which monitors 3 other temps.
http://www.azeltec.com/images/brochure.pdf
Stratification, yes you can see the temps climb while loading, to the tenth of a degree. It works well for a monitoring tool. The other temps I look at are the return to mixing valve at boiler, post mixing into boiler and system supply (boiler out).
I would not do any extra cutting into tanks than necessary. 
The ends of the 1/2" pipe are welded in with a continuous bead for heat transfer and then a couple of spot welds out on the ends. Everything was sprayed with foam.
Any changes. No. Not with the thermometers or the tank set up in general. Been very happy.


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