# Help with storage plumbing



## warno (Feb 14, 2016)

I received my used propane tanks yesterday and would like to get started on putting in my ports as soon as possible so I can get started on the install when spring hits. I have two 250 gallon tanks that are going in horizontal in my crawl space. I'm needing advice on plumbing the 2 tanks to work with my system. I'm using a HX in the current duct work of the natural gas  furnace, and I'll be running a sidearm for DHW. 

I have this drawing that I made hoping this would be a good starting point. 





The supply manifold would go in the top of the tanks and the return in the bottom. I drew them on the boiler manifold, but I wasn't sure where to plumb the HX and sidearm. either the boiler manifolds or build their own manifolds? Could anyone help me out with this plumbing? If any other information is needed let me know.


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## lotawood (Feb 14, 2016)

The drawing makes it look like the tanks are vertical.  Is that what you wanted to say, instead of horizontal?

Might want to add a check valve on the output of the boiler, if there isn't check valves on the pumps.

You could run the lines for the plenum  HX  straight to the boiler lines and balance the flow


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## warno (Feb 14, 2016)

I'm definitely no artist by any stretch but I did mean horizontal when I wrote that. I only have very limited head room in the crawl space so I have to have horizontal tanks. The pumps I'll be using will have check valves in them.


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## leon (Feb 14, 2016)

warno said:


> I received my used propane tanks yesterday and would like to get started on putting in my ports as soon as possible so I can get started on the install when spring hits. I have two 250 gallon tanks that are going in horizontal in my crawl space. I'm needing advice on plumbing the 2 tanks to work with my system. I'm using a HX in the current duct work of the natural gas  furnace, and I'll be running a sidearm for DHW.
> 
> I have this drawing that I made hoping this would be a good starting point.
> 
> ...


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


Before you go any further:

Please order at least 2 of Dan Holohans books from Amazon. 
The first one is "Pumping Away" and the second one is Classic Hydronics".
With these tow books your going to prevent the mistakes you now have on paper
long before you start hacking and whacking. 

Trust me the books are worth every penny and they will save you thousands of 
dollars in mistakes-they did for me when I installed my Keystoker Coal Stoker boiler.

Unless your crawl space is insulated I would seriously consider changing the location of the tanks.
The ground temperature is going to be 52 degrees or lower in the crawl space and your propane tanks are 
going to shed heat to the ground.

you will lose more heat to the ground than the tanks will give off to the floor, yes you will.  

You need to revise your plumbing as well- the tanks need to be plumbed in series not series parallel this is only going to make 
a mess for your plumbing and you will have no point of pressure change in that mess and your water is simply going 
to sit there and not move. 

Where is your Pump?? I hope it is on top of the boiler because you are going to be pushing a lot of air through the system 
unless you change the tank plumbing to series plumbing.

if you install a steel expansion tank you will have a much easier time in doing plumbing and not require an air scoop 
and the steel expansion tank will not fail like a bladder expansion tank will- We just changed the one on my father 
boilers that has been bad for 2 years as my brother did not know what he is doing-typical.


Please Order the two books I mentioned as Dan helps the layperson and the plumber both understand hydronic heating. 

I am just trying to save you thousands of dollars and headaches.


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## lotawood (Feb 14, 2016)

I am not a plumbing expert.  It was suggested to me to study Nofossil simplest storage diagram when I did mine.

I copied that design.  I have a whole lot less going on than he does.

I thought a key item was how the boiler loop is tee'd into the distribution loop.  That is what I copied.  Mine works fine with zone valves on the distribution loop.  You don't look to have zone valves.

You could think about piping in series thru 2 250 gallon tanks.


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## warno (Feb 14, 2016)

I will have a pump pushing water from the tanks to the boiler which with the boiler being the high point in the system i would think should draw the water back down to the tanks.  I'm curious what makes plumbing the tanks in series  versus  parallel is better? If the tanks have manifolds on the inlets and outlets wouldn't that make them act as "one" tank.  I wasn't going to use zone valves but instead run my HX pump with a call for heat from the furnace. My DHW pump would run constantly.


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## leon (Feb 14, 2016)

Please order Dan Holohans books.

ALL the water used for heating will move from one tank to the other.

The way you have your drawing the waters not going to move unless you have two circulators at the base of each tank making them nurse tanks and pulling water from them and pushing it to the heating load.

Your "single circulator" is going to be pushing against the total head pressure of the entire volume of water in the two tanks and then back up into the heating load.

YOU have to understand water is lazy just like electricity and will do what ever it wants and go where ever it want to unless you control it, plumb it right the first time, and make it go where you want it to.

Think of a marble traveling down the piping and follow it from the beginning to the end-at every tee the marble is going downhill,

The "Circulator" has to be on top of the boiler to eliminate air bubbles and slugs of air and doing this prevents circulator cavitation. 

Your water is not going to move very well period!! like I said and the temperatures will stratify and "all" the water in storage will not be heated because it cannot be moved to the boiler and back again and the tanks will shed heat in to the crawl space.

Every restriction you install creates more head pressure and more resistance. Flooded suction for a circulator is best to push the hot water to the heating load.

I do not want you to attempt herding cats when you do not need to.

Its better to have the tanks as return buffer tanks to the boiler sump with the circulator pulling the water from the top of the boiler pushing the water to the heating load as the boiler will fire less.


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## warno (Feb 14, 2016)

I don't know of it matters but I planned to do batch burns with this storage where the boiler pump will only run while the boiler is burning it's fuel then after the tanks are charged it will shut down and the HX pump will kick on/off with heat load and the DHW will run all the time. I can put the charging pump at the boiler that's no problem. 

But I'm still confused why series tanks are better then parallel? I have seen many systems on here using parallel tanks and those people have posted having great results. 

And you mentioned that I'll be losing heat to the ground. If I'm insulating the tanks how will I be losing heat any more then if I put the tanks right in my living room? I understand if I left them bare I will be losing a ton heat but with the insulation doing it's job should combat this loss,  right?


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## leon (Feb 15, 2016)

warno said:


> I don't know of it matters but I planned to do batch burns with this storage where the boiler pump will only run while the boiler is burning it's fuel then after the tanks are charged it will shut down and the HX pump will kick on/off with heat load and the DHW will run all the time. I can put the charging pump at the boiler that's no problem.
> 
> But I'm still confused why series tanks are better then parallel? I have seen many systems on here using parallel tanks and those people have posted having great results.
> 
> And you mentioned that I'll be losing heat to the ground. If I'm insulating the tanks how will I be losing heat any more then if I put the tanks right in my living room? I understand if I left them bare I will be losing a ton heat but with the insulation doing it's job should combat this loss,  right?



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

You have no where in the home structure where you can install these 
tanks by the boiler??

Insulating the tanks is fine but with the tanks below and the boiler above them its still 
not going to work well or very well with your plumbing diagram.

Order the two books I told you about and you will not not be making costly mistakes.


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## warno (Feb 15, 2016)

There is no room in the house for the tanks and my boiler is an outdoor unit about 80 feet away. 

Basically I'm trying to do what the attached picture is. Boiler charging the tanks, in parallel, and loads pulling from the tanks. Only difference is my tanks are horizontal not vertical. I suppose this drawing might be what you meant but "series parallel"? But either way that's what I'm trying to do. 2 tanks, 2 loads, and 1 boiler.


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## leon (Feb 15, 2016)

If you can pour a slab and put a small shed by your boiler you would be able
plumb this a lot easier as you could keep wood in it and the tanks keeping them vertical 
making your plumbing much more easy to install.

Your water is still going to be difficult to move the way your drawing is currently illustrated 


At least I would like you to buy the two books I mentioned only for your peace of mind 
as your making more work for yourself.

Disclaimer: I have no financial interests with Mr. Holohan or his publisher in any way.


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## warno (Feb 15, 2016)

My drawing was simply a starting point of what I thought might work. That's why I started this thread for advice on how to make it better. 

My problem with putting my storage anywhere but in the crawl space is I don't have the room in my yard for more outbuildings. I know plumbing them will suck with the low head room, but once it's done it will be done. I know is possible to do this I'm just looking for advice on the best way.  

I'm glad to read that you have no beneficial gains from those books because I'm not going to lie I was starting to think that. Lol


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## Bob Rohr (Feb 16, 2016)

Maybe this journal will help with some of your decisions.  Ideally a single, tall, vertical tank is best for storing energy.  You do want to stratify the tank, and vertical tanks allow for the best "stacking"  In these drawings the tanks, of course could be horizontal.

One key concept is two pipe configurations.  This allows all or any portion of the boiler output to go directly to the load.  There in no reason to interface the tank volume when a load calls and the boiler is firing.

As the load lessens and or eventually satisfies all the output recovers the tank.  then on the next call, energy comes from the tank if the boiler is off line.

Pay attention to the explanation of Extergy on page 6, this holds the key to stratification benefits.

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_17_na.pdf


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## velvetfoot (Feb 16, 2016)

An excellent read.  Though not a cord wood burner, I'm liking Fig 5-12, for simplicity.

Isn't it normal to have a pump or loading group to pump to boiler return?  Most diagrams seem to have it this way.

Why only 500 gallons?  (Logisitcs, I'm sure.)  I recall your homebuilt gasifier is a monster.



Bob Rohr said:


> There in no reason to interface the tank volume when a load calls and the boiler is firing.


Although the cool tank bottom water, or portion of it, still goes back to the boiler.


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## warno (Feb 16, 2016)

Yeah it will be my home built boiler that I'm using. It's not a gasser though. I wish I would have built one, that's my 3 year plan. I plan to get this storage up and running for next winter then with any luck for the following winter I'll build a new boiler. 

I'm only running 500 gallons because that's what I have room for. The storage is only heating my home which is  about 1100 square feet. I'll read through that link posted and report back.


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## velvetfoot (Feb 16, 2016)

warno said:


> 1100 square feet


Wow, I remembered your boiler being pretty big.


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## lotawood (Feb 16, 2016)

The idronics PDF's were very helpful in understanding a lot that gets talked about in the boiler room for me.

The Tarm diagrams and the simplest storage sticky also helped in planning my system.

Warno if you build a new boiler will it be a closed system/pressurized?  I think you have an open system now and some of the drawings above are for pressurized systems.


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## warno (Feb 16, 2016)

My boiler used a 30" diameter X 45" long propane tank for a fire box with a 7 feet long 6" X 10" heat exchanger over top of it. Heating about 120 gallons in the water jacket.  I'm reading 450 degree flue temps. I'm working on getting better combustion and lower flue temps at the moment. 

I actually talked to our inspector at work about the cost of a U stamp for a pressurized boiler.  After hearing the cost of the stamp I probably won't go with a certified pressurized system. But I might still build a well supported pressurized boiler with the proper stay rods and relief valves. 

I have previously  read through the PDF that was posted but I'm working through it again. I'm starting to consider making my storage pressurized with a plate heat exchanger to  charge it. I'm still trying to figure out  my piping I need though.


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## maple1 (Feb 17, 2016)

I'm thinking you will get better stratification if you plumb them parrallel. Then the flow will be roughly 2x slower through each. But when it comes right down to it, it might not make much noticeable difference - mine are stacked, but piped in series, and I see good stratification. 'Fine points' like getting your inlet & outlet tappings as close to pointing horizontal across the tank might play a bigger part (and as close to the top & bottom as possible) - more downward/upward flow there would lead to more mixing and less stratification.


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## warno (Feb 17, 2016)

So I'm getting alot of series and parallel being better or worse. And I'm getting very confused from that.

So as far as just the inlet and outlet on the tanks. I was going to use a piece of 1.5" pipe to make my "manifold" pipes between the 2 tanks then tie my 1" supply and return from boiler lines into the center of those manifolds. The inlet and outlet in the tanks were going to be as high, inlet, and as low, outlet,  as possible. I planned to use a diffuser that I'll build for the supply lines. I'll simply take a section of pipe and weld a block off plate in the end then drill many holes down the length of that pipe 180 degrees from each other. The line of holes was going to be layed "flat" in the tanks to direct incoming supply water outwards instead of jetting straight in.

So as far as my original drawing goes, on just tying the tanks together, would the parallel as drawn work for me?


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## leon (Feb 17, 2016)

warno said:


> So I'm getting alot of series and parallel being better or worse. And I'm getting very confused from that.
> 
> So as far as just the inlet and outlet on the tanks. I was going to use a piece of 1.5" pipe to make my "manifold" pipes between the 2 tanks then tie my 1" supply and return from boiler lines into the center of those manifolds. The inlet and outlet in the tanks were going to be as high, inlet, and as low, outlet,  as possible. I planned to use a diffuser that I'll build for the supply lines. I'll simply take a section of pipe and weld a block off plate in the end then drill many holes down the length of that pipe 180 degrees from each other. The line of holes was going to be layed "flat" in the tanks to direct incoming supply water outwards instead of jetting straight in.
> 
> So as far as my original drawing goes, on just tying the tanks together, would the parallel as drawn work for me?


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

I have one question; if you have room for a OWB and firewood why is it you cannot add a small shed for wood 
and the tanks you bought to plumb them properly?


Please order the books "Pumping Away" and "Classic Hydronics" from Amazon before you make your problems worse. your going to spend a lot of money that you do not need to spend.

At least consult a licensed plumber and pay for an hour of his time.


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## maple1 (Feb 17, 2016)

*So I'm getting alot of series and parallel being better or worse. And I'm getting very confused from that.*

That might just mean, 6 of one half dozen of the other - there might not be one 'right' answer and it might not make much difference.


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## warno (Feb 17, 2016)

leon said:


> =====================================================================================================
> 
> I have one question; if you have room for a OWB and firewood why is it you cannot add a small shed for wood
> and the tanks you bought to plumb them properly?
> ...



Since I'm in town, After adding my current boiler shed I have now it has taken up enough space on my lot that the city wouldn't give me my building permit for another outbuilding. So I'm stuck with putting them in the crawl space. 

I understand that vertical tanks are best but why is it that one cannot plumb horizontal tanks correctly?


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## Bob Rohr (Feb 17, 2016)

warno said:


> Since I'm in town, After adding my current boiler shed I have now it has taken up enough space on my lot that the city wouldn't give me my building permit for another outbuilding. So I'm stuck with putting them in the crawl space.
> 
> I understand that vertical tanks are best but why is it that one cannot plumb horizontal tanks correctly?


Sure you can pipe tanks in a horizontal orientation.  The fluid circulating thru the tank really doesn't know or care how the tanks are placed.  There are plenty of tank, especially the re-pourposed LP thanks that are still "on their feet"
>


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## lotawood (Feb 17, 2016)

I think two horizontal tanks plumbed in parallel should be just fine.  

I have one tank plumbed horizontal that works well.  I just wish I had more than 500 gallons.  I think vertical is optimal.  Horizontal works OK for the stratification.

Two horizontal in parallel, plumbed with the supply and returns not pointing down/up:  I think there is plenty of people here with that.


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## Pat32rf (Feb 21, 2016)

Used to do this for domestic hot water in 30 floor apartments with electric boilers....Parallel can work IF you can balance them (start with "reverse -return" piping) but series systems are a lot easier to monitor and stratify, especially with horizontal tanks. 
I like the crawl space idea provided you insulate the walls and the tanks....


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## warno (Feb 21, 2016)

I was going to get the walls spray foamed in the crawl space after I put in my vapor barrier. And the tanks will be foamed as well after leak checking. 

So let's talk series on the tanks. How do I plumb my supply and return on the series setup? Supply in the top of tank 1 then out the bottom of tank 1, into the bottom of tank 2 then out the bottom of tank 2 to return to the boiler? I'm confused about the return from 1 and supply to 2 where do the go? Top or bottom?


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## maple1 (Feb 21, 2016)

I would go from boiler to top of tank 1, then bottom of tank 1 (opposite end) to top of tank 2, then bottom of tank 2 (opposite end) back to boiler.


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## warno (Feb 29, 2016)

I redrew my drawing in hopes that it would have less confusion. I'll describe what I'm doing then post the pics. Please let me know if this will be ok or not. Any questions or concerns please let me know. I'm wanting to get started modifying my propane tanks as soon as possible.

Basically I'm going to be batch burning. So my "boiler to storage" pump will only run while a fire is burning in the box.

Pulling from storage I will only have my HX in the furnace ductwork and my sidearm for DWH. The HX pump will only run with a call for heat and the sidearm pump will run constantly.

So here's my drawing.

First just boiler to storage plumbing. I marked on the paper "top view" but this would actually be side view.  Also, The tanks are side by side not over-under





This one is storage to system plumbing. Blue line is DHW loop and red line is furnace  HX loop.


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## warno (Mar 2, 2016)

Today I did some measuring and thinking about the whole system. It turns out with a little work I can put my storage tanks vertical in my garage. But it raises a few more questions I would like help with. In order to do vertical tanks I will have to do pressurized storage with my open boiler. Which I know requires a heat exchanger.

So that leads me to my first question. How do I size a heat exchanger to heat storage tanks? Everything I'm reading gives me DHW or radiant floor or snow melt options. But I couldn't find anything to help me get a plate count for heating storage.

The other potential problem with my storage in my garage is the tanks will be about 120 feet one way to my furnace HX and my DHW sidearm. I wanted my DHW to have consistent flow and my furnace HX was going to run with call for heat. So my next questions are, how do I plumb my HX and my sidearm to run like I wanted them to? Could I put manifold in my crawl space then have my pumps pulling from that manifold? Or how is the best way to do this? Is it ok to constantly pump water underground from storage to house to run my sidearm? I'll be running 1" thermopex for my underground lines.

Any help with this new idea would greatly be appreciated.


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## Bob Rohr (Mar 3, 2016)

warno said:


> Today I did some measuring and thinking about the whole system. It turns out with a little work I can put my storage tanks vertical in my garage. But it raises a few more questions I would like help with. In order to do vertical tanks I will have to do pressurized storage with my open boiler. Which I know requires a heat exchanger.
> 
> So that leads me to my first question. How do I size a heat exchanger to heat storage tanks? Everything I'm reading gives me DHW or radiant floor or snow melt options. But I couldn't find anything to help me get a plate count for heating storage.
> 
> ...




This is a hybrid series/ parallel piping with loads and input as a "two pipe" method.

The tank connectors need to be large and short as possible, 2" pipe perhaps.  same for the S&R headers off the tank.

The concept is heat from the boiler can go directly to the loads without first heating the tanks.  as the load drops and tanks get to temperature heat is drawn from the tanks.

I would still run the DHW on a thermostat, no need to allow DHW to get to 180 of hotter by running continuously.[


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## goosegunner (Mar 3, 2016)

Do you have anything planned for return boiler protection?  With storage you will have extended time periods of low return temps if you don't have some way to regulate the return temp.


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## goosegunner (Mar 3, 2016)

If you use a always on with a side arm for DHW you will be mixing your tank to one temp. Not really what you want with Forced Air exchanger in the system.  Probably better to have a flat plate with on demand pumping. When doing that you might want to consider having a small buffer tank near the DHW.

A few difficulties with remote storage and DHW.

1. You don't want to mix main storage tank so circulate on demand is best.

2. DHW you want near instantaneous heat. Pumping on demand will cause a delay, especially on low demand space heating days.

3. Use of small buffer tank and demand style flat plate will require more controls to compare main storage to buffer temps and replenish when needed.

Another option would be to have a DHW coil in the small buffer tank. Make sure your Domestic water is stable quality if you choose this route. Not an option where I live as water is slightly acidic and aggressive if thermo-siphoning through cooper pipes.


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## warno (Mar 3, 2016)

I will have boiler protection via a thermomix valve on the boiler side. 

I could run my sidearm pump with a temp control so it doesn't have to run all the time it would only run to keep the hot water up to temp. If a high demand situation came up then it would just run the gas burner. I'm ok with that. 

So would my idea of a manifold or small tank in the crawl space, with my HX and DHW pumps pulling off that work. I'm thinking I could pump my storage water to this manifold when there is demand from either DHW or the furnace. I could also keep a temp sensor on this manifold to run the storage pump to keep a minimum temp in this manifold. 

Does that make sense? It seems more simple in my head when I think about it but it reads complicated.


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## warno (Mar 3, 2016)

Another question here. If I'm going to run my storage pressurized will I need an expansion tank also?


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## maple1 (Mar 4, 2016)

IMO any pumping of water from storage, when it is not needed, will end up decreasing the usefulness of storage. It messes up your stratification, and decrease how long you can effectively heat off the storage. I have manifolds, 5 zones each with a zone valve, and one pump (Alpha) that gets started when any of the zone valves open on a call for heat. It pumps slow to maximize stratification - but how slow you can go would depend how much heat your loads need over a certain period of time.

Will you be trying to heat DHW with the sidearm off storage in non-heating seasons?

Yes, any time you have a pressurized system, you need expansion. Amount of water in that system determines how much expansion.


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## warno (Mar 4, 2016)

So maybe running my "from storage" pump to a manifold only with a call for heat and then just use zone valves instead of circs to run my loads? Would that be a better way to run it?  

I don't plan to run the system in the off season. Only during the heating months. So my DHW will just run as it does now through the summer mouths. 

I haven't decided on complete gallons of storage yet but its either going to be 500 or 750. I already have my 2) 250 gallon tanks but If I can get another tank it will be the 750. How much expansion do I need for 750 gallons at 180 degrees? 

Also could anyone tell me how big of a plate heat exchanger I need for charging my storage? My boiler is homemade so I don't know BTU output but I could figure out how quick it can make up temperature in my current setup. So basically I'm hoping I can size my heat exchange  off of temp and flow alone.


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## Bob Rohr (Mar 4, 2016)

www.flatplatselect.com for a free sizer program
www.amtrol.com for an expansion tank sizer


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## warno (Mar 4, 2016)

I plugged in some numbers on the HX on came up with this 





I did a quick test on my boiler. I'm running about 3 gpm through it now with about 150 gallons in the system and I picked up 10 degrees in 7.5 minutes. So could someone smarter than me tell me if my boiler could keep up with 6 gpm? 


The expansion tank calculator said I only needed around a 10 gallon tank. That seems really small, but then again in still new to all this.


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## leon (Mar 5, 2016)

warno said:


> I plugged in some numbers on the HX on came up with this
> 
> 
> View attachment 176212
> ...


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




If you invest in a steel expansion tank in that size bracket it will have volume of 15 gallons in total-10 for water and 5 for the air cushion and you will be very happy with the five gallon air cushion.

They work perfectly when they are plumbed properly with the airtrol valve which removes the micro bubbles and holds them in the tank forever. Mine is working very well and providing another 10 gallons of water to add to the water mass of the boiler.

You can install a bigger steel expansion tank with no issues and you will be glad you did.


Yes Warno, you will be glad you invested in a steel expansion tank; OH, and you can buy a much larger steel expansion tank and add that much more water-thermal mass to your boiler and your circulators will be quiet and not create water fall sounds in your heating system and you will be glad you did. I did it and I am glad I did it and I wish I had done it 33 years ago.

AND you will never have to worry about the rubber bladder failing as there is no rubber bladder in the steel expansion tank. 

my fathers bladder expansion tank failed after five years and caused the boiler to have blow offs until they changed it and it will fail again in five years.


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## warno (Mar 5, 2016)

Does a steel expansion tank need to be mounted above the storage tanks or can it be set on the floor next to the storage? I'm thinking above to allow the air pocket to stay where it should but I want to double check.


Another question, if I'm looking for 6 GPM on both sides of the plate HX shouldn't a grundfoss 15-58 be enough pump to run on both my boiler and my storage side?


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## leon (Mar 5, 2016)

If you can park that expansion tank above the water supply to take advantage of the height to maintain a lower pressure on the system(attic preferred or at ceiling height hung above the tanks in the room where the trap door is all the better otherwise you will have to deal with a bladder tank and air scoop=YUCK = more plumbing


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## warno (Mar 9, 2016)

Couple more questions,

With the airtrol fitting is an air separator needed or is it simply plumbed into the tank and tied into the system?

probably a dumb question but, where does my pop off valve go in the sealed system?  In the expansion tank?

And what happens if I don't put in a big enough expansion tank?


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## leon (Mar 10, 2016)

warno said:


> Couple more questions,
> 
> With the airtrol fitting is an air separator needed or is it simply plumbed into the tank and tied into the system?
> 
> ...


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

First question;

The airtrol fitting goes in the bottom of the horizontal steel expansion tank.
The Inline Air separator comes off the top of the boiler and the tapping on the top 
of the inline air separator being 3/4" is piped upward to the steel expansion tank.

An IAS can be used with a large commercial air separator but the steel expansion tank 
and airtrol valve installed in the lower tapping are much less trouble and have no moving parts.

Your relief valve is installed in the top of the home boiler steam chest nowhere else, and the system pressure 
should not be higher than 12 pounds Per Square Inch with the boiler operating.

Your expansion tank is sized based on the size of the interior boiler and heating loop volume.

My 15 gallon expansion tank is more than adequate for my total volume of 54+- gallons which is the boiler volume + the 10 gallons in the expansion tank and the 7 gallons in the heating loop.

If your tanks are fully open to the interior boiler feeding the steel expansion tanks from one IAS you could use 2 15-gallon tanks plumbed in parallel with 2 airtrol valves being plumbed into a common header pipe connected to the two airtrol valves in the base of both tanks. 

The B+G folks have sizing charts for expansion tanks.


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## warno (Mar 10, 2016)

I don't have a boiler in my house. This is all plumbing from my pressurized storage in my garage. My boiler is an open system OWB. I'm charging storage through a plate HX. 

So with that said, in what location should my popoff valve go?

  Also all the calculators I have found and plugged my numbers into come up with me needing 30-40 gallons of expansion. That doesn't seem like much For 750 gallons at 190 degrees maximum. Could someone double check for me on that size.


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## leon (Mar 10, 2016)

warno said:


> I don't have a boiler in my house. This is all plumbing from my pressurized storage in my garage. My boiler is an open system OWB. I'm charging storage through a plate HX.
> 
> So with that said, in what location should my popoff valve go?
> 
> Also all the calculators I have found and plugged my numbers into come up with me needing 30-40 gallons of expansion. That doesn't seem like much For 750 gallons at 190 degrees maximum. Could someone double check for me on that size.


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



The only place you need and want a pop off valve is the steam chest of the fossil fuel boiler or wood and coal boiler. with an unpressurized boiler you have the expanse of air above the water level.


In the sealed portion of the system: 

You need to install the tanks the pair or triple of the steel expansion tanks goes in the highest point in the system by hanging the tanks in garage ceiling using a common header pipe to the two or three steel expansion tanks outfitted with an airtrol valve in each steel expansion tank.

you can simply mount a single circulator for the heating loop above the storage tanks and pull the water up from the tanks and avoid a lot of issues with trapped air bubbles.

Is there any real reason besides expense you cannot run a second DHW insulated pex tubing line from an external DHW coil the garage with a simple watts mixing valve in the home to keep the water at 120 degrees before entering the fixtures???

Its so much easier to run second pair of lines for the domestic hot water in this way in the same trench eliminating all the extra plumbing in the home.


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## warno (Mar 10, 2016)

So on my pressurized storage I don't need a pop off valve at all? 

I'm already  running about 90 feet of thermopex to the house from garage and at $11/foot it adds up real fast so a second line underground is out of the question on cost alone. If it comes right down to it I'll just not heat the DHW off the boiler and simply heat the house. Our DHW heater doesnt use alot of gas anyway so if I'm saving money on just heating the house I'd still be happy. 

I'm planning on only having 1 expansion tank. If I can't find a used propane tank to suit my needs I'll build a tank to fit. So I only need one airtrol fitting. 

Another question here,  if I put a fitting dead center of my storage tanks, could I plumb that to the airtrol fitting instead of using an air scoop in the line? Wouldn't any air bubbles that get pushed into my storage  tanks from the system go to the top then move into the expansion tank?  Or would I still have air bubbles getting into the loop?


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## leon (Mar 10, 2016)

warno said:


> So on my pressurized storage I don't need a pop off valve at all?
> 
> I'm already  running about 90 feet of thermopex to the house from garage and at $11/foot it adds up real fast so a second line underground is out of the question on cost alone. If it comes right down to it I'll just not heat the DHW off the boiler and simply heat the house. Our DHW heater doesnt use alot of gas anyway so if I'm saving money on just heating the house I'd still be happy.
> 
> ...


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You cannot use and should not use an air scoop along with an airtrol valve and tank as the tank with its air cushion is what
controls the pressure in the heating loop and boiler.

Building a tank is not a good idea or proper plumbing code/legal.

It would be much simpler and safer for you to invest in either a 30 gallon B+G tank and the proper size B+G airtrol fitting for your system. You may find that all you need is the fifteen gallon tank and airtrol valve as your heating loop system is not that 
large to begin with and you can use lower temperature water to its advantage as you can only provide so many BTU per gallon of hot water for heating no matter the temperature.

Once you purge the system of air you will have no air bubbles or waterfalls.


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## warno (Mar 10, 2016)

If I build my expansion tank I'll do it at work, we build industrial refrigeration units. I'm an ASME certified welder and we have the parts and testing equipment to build such vessels. I'm not worried in anyway about building the tank I would have to buy the parts from work, but I can source propane tanks for next to nothing. 

So would me putting fittings in the top center of my storage tanks be ok then tie them to the airtrol fitting in the expansion?


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## biothermic (Mar 10, 2016)

Great questions warno.  Bob Rohr has given you fantastic advice. I echo all his comments.  Make sure you put the DHW circulator on an aquastat.  Side arm style heat exchangers are commonly installed with continuously running circulators which destroy the thermal stratification in the buffer tank.  Vertical tanks with thermal stratification are critically important for efficient operation. 

Here is a link to a general schematic showing one possible location for the expansion tank. 

http://www.biothermic.ca/assets/printouts/FHG Typical.pdf


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## leon (Mar 10, 2016)

If your determined to make the expansion tank yourself I would be sure to follow the B+G 
recommendations for the one inch airtrol valve. IT has to be connected to the bottom tapping in 
the tank as illustrated in the tank examples AND the water level in the tank cannot exceed 2/3's 
of the horizontal height of the tank as discussed in the drawings and sizing chart.

For the amount of water you have or propose to have in storage you need the next larger airtrol valve being one inch
and a 30 gallon tank AT LEAST for the water volume as you must  have a one inch common header pipe that 
comes off the tow storage tanks and will be connected to the 45 degree riser that attaches to the one inch airtrol fitting in the horizontal tanks tapping. You can use unions for these connections with no issues.

This is why I suggested the 30 gallon B+G tank and the one inch airtrol for your installation as they are pressure and leak tested and it will work right out of the box with the 1" airtrol fitting. The only thing you need are reducing bushings, pipe strap, pipe plugs and you have to decide if you want the water glass gauge which is a must when filling the system as you will know how much water is in your system if you want to check it as the airtrol valve has no restrictions to flow


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## warno (Mar 10, 2016)

We actually have purpose domed tank ends for expansion tanks that we build for glycol cooling units at work. We pressure test them at 250 PSI.  The only reason I would build my tank is if I can't find one that clears my duct work in the attic of my garage. We have a Taco brand expansion tank at work, that a was purchased then not needed,  that I can copy fitting locations from.

I think I'm going to avoid the DHW loop for now and focus on the just heating the house. I'll draw up another sketch and see if I'm on the same page with everyone.


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## warno (Mar 10, 2016)

Here's what I'm thinking. Please tell if it's ok or wrong or what to fix.

First I have the OPEN system OWB pushing water to my plate HX. This loop has the boiler protection valve on it.

Then from plate HX to my storage supply manifold. This manifold will be 1.5" pipe reducing at second tank to 1" then reducing again at third tank to 1/2". Correct me if I'm wrong but I think this is called reverse return parallel piping. The return line goes to the third tank at 1.5" then reduces to 1" at the second tank then again to 1/2" at the first tank. So that covers storage.

From my storage supply manifold I'll use a delta T pump to push water 90 feet through underground lines to the house to a manifold in the crawlspace made of 2.5" pipe. This manifold will have 4 ports and then the supply and return to storage. I'll tie into 1 port for my furnace HX then use another port back into the manifold with the return from HX. The 2 remaining ports will remain unused until I figure out what I want to do with my DHW. Then water returns from the manifold back to the storage tanks return piping.

Expansion is going in attic space in garage with fittings in the tops of all three tanks pitched to the final tank then a line ran up to the airtrol fitting.

Again please tell me if I'm getting close or I'm way off.


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## ewdudley (Mar 11, 2016)

warno said:


> Expansion is going in attic space in garage with fittings in the tops of all three tanks pitched to the final tank then a line ran up to the airtrol fitting.


Putting the expansion tank in the attic is ideal (assuming it can't freeze).  No need for an airtrol.  The airtrol is for separating gas from water flow leaving the boiler.  In your design the gas goes to the storage tanks and migrates to the expansion tank with no need for an airtrol.

Note that all volume above the upper supply ports on the storage tanks, and all volume below the lower ports on the storage tanks will be lost for heat storage purposes.  In many implementations this can amount to well over a third of potential storage volume being wasted.

But all you need to recover the wasted volume is to run riser tubes up to near the top of the tanks and dip tubes down to near the bottom of the tanks.


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## warno (Mar 11, 2016)

What is the ideal location from top and bottom for the supply and return lines? My drawing is rough but I was thinking 6" down from top and 6" up from bottom. I don't have any experience to  back up those measurements it was just an assumption. 

Also, if it matters, I was going to build my inlet and outlet pipes to the storage with horizontal holes and end plates on them to act as diffusers to help avoid jetting the water into the tanks.


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## warno (Mar 11, 2016)

Am I on the right track with my new drawing? Should I change anything about it or run it like drawn?


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## leon (Mar 14, 2016)

As EWDudley has said the inlet and outlets location will cause
you to lose water volume as far as reclaiming available heat goes.
installing riser pipes for the suction of the hot water and dip tubes
for the discharge of the cooler return water in each tank will work well.

As for welding in diffuser's that is something that is not required as the water is
not really in any need for diffusion.

You need to worry about being able to drain sediment with three boiler drains
and installing  one zinc anode in each tank with three more weldment's for the
zinc anodes in the half way point in each tank.

Why are you using three circulators when you only need one!????????????????????????????
your hot water flow is backwards it needs to enter the tank at the bottom preferably so you can use just "one" circulator pulling the hot water off the top of the three tanks after the steel expansion tank pushing the hot water to the heating load. You can install the external domestic hot water coil anywhere after that and they will not plug as readily as a flat plate heat exchanger as I describe below. 


Remove the 3 circulators from your drawing!! The two circulator's that are closest to each other are not going to help you, they will just make more air bubbles and the point of pressure change will be confused and create cavitation issues with the three circulators.

AN external domestic hot water coil would be easier to use and easier to manage as there is nothing obstructing water flow just one in tapping and one out tapping for the boiler water and the domestic
coil will provide 5 gallons per minute of hot water all the time.

The other advantage is the copper coil will not plug for a long time if ever. My external Domestic Hot Water Coil set up delivered hot water for 34 years without plugging and my Keystoker has the same type of coil in the steam chest of the boiler.


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## warno (Mar 14, 2016)

I was thinking the diffusers would slow the water from jetting straight into the tanks and would divert water horizontally.

I didn't draw anything like drains, valves or ect. small parts because I'm just trying to get the flow and plumbing correct. I will have drains and everything in the final install. I don't think I need anode rods in the  tanks because they will be pressurized and everything I've read says once the O2 is used up it should be fine.

I'm confused how it only need ONE circ. When I'm running one from boiler to HX, one from  HX to storage, and one from storage to house. Right there is 3.

With my storage tanks tied to my expansion tank via fittings in the top air bubbles shouldn't be an issue. Because anything in the lines will be forced to storage then picked up in the expansion header.

I'm wondering if you read my description of the drawing or just looked to the drawing? Like I said in the beginning I'm no artist.



I drew up a quick thought for my tank inlets/outlets. The pipes would run in to an elbow and then up or down to my diffuser. Again the "diffuser" design is an end plate on the pipes then a series of holes drilled into the pipe's side.


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## leon (Mar 14, 2016)

You do not need to have diffusers in the tanks, Large commercial laundries and institutional laundries
have hot water storage tanks do not have them-the hot water goes in and the water goes out to the 
end use whether its a large commercial washer or steam ironing system. 

You do need the dip tubes and riser tubes WITH NO HOLES.

You need the sacrificial anode rods because of the hot water and its changed chemistry. 
You need the anode rods as the anode rods attract any corrosive chemical imbalance 
in the water to them and they sacrifice themselves to counter any issues with the water PH
and they become lunch rather than the tank walls.


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## maple1 (Mar 15, 2016)

I don't think anode rods are needed in a pressurized system.


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## leon (Mar 15, 2016)

All you need to do is install "one" circulator drawing the hot water water off the header pipe
that is connected to the steel expansion tank.

you can do this with a Tee and two isolation valves for one circulator.

This is exactly how my system is plumbed and it works very very well.

The resistance created by the heating load is the issue for you and
one circulator is plenty for this if you use zone valves for the individual
loads.

My B+G NRF25 circulator has three speeds and the lowest sped is
17 gallons per minute and that would be plenty for your needs and
as it has two higher speeds and you can always increase the
water flow in the heating load.

All you need is one circulator and some proper system design work
and you will be fine.The B+G folks will help you with this simply by asking them.

I want you to succeed not fail. I am not trying to stop your progressing with
your plumbing I am just trying to help you avoid the problems you are making
for yourself in your current drawings.

Your going to have a lot of air bubbles unless you install the circulator in the
header pipe coming off the top of the tanks. The steel expansion tank will
still work fine just like my set up-you need to add a ball valve to shut off the
steel expansion tank too. You need more ball valves preferably 2 at
each tank and several more to shut off the separate heating loads as you
will have to refill the steel expansion tank and drain off the excess water to
create the proper air to water ratio in the steel expansion tank each time.   

Most water heaters have sacrificial anode rods so keep that in mind
and they are not that expensive either as they are cheap insurance since
you are building your own tanks from used propain tanks.


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## warno (Mar 15, 2016)

As I said above I will have all the valves I use as needed. I just didn't draw them in.

My supply to house line is coming of my top manifold from my tanks and return to bottom manifold.

If you read my description of my drawing, all my manifolds are over sized. I'm using circs instead of valves. And I did my drawing off of the thought of "primary secondary piping" but using my storage instead of a boiler. My from storage to house runs underground to an oversized manifold(primary loop) where my HX circ. will pull what it needs to heat house on call.(secondary) The return will enter same manifold 6" away where it will mix with some hot supply then head back to the storage tanks return via the initial circ. which for added savings of temp I'm going to run a delta T pump.


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## warno (Mar 17, 2016)

Any other advice for me on the new drawing in post 53?


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## ewdudley (Mar 18, 2016)

warno said:


> Any other advice for me on the new drawing in post 53?


Leaving the plate HX, arrange for piping to convect gently towards storage.  Then use a simple aquastat on the pipe leaving the HX to control the HX-to-storage pump according to some minimum temperature so that storage does not get mixed by constant running of the HX-to-storage pump.  This will help minimize the temperature of the water entering HX from bottom of storage and will thus maximize the effectiveness of the HX.

The DeltaT pump (or its sensors) should be moved to the house so the sensors can see sooner what's going on with the house manifold.  Also it would seem preferable to me to run the storage-to-house ("Delta-T") pump as a setpoint-T pump with outdoor reset.  (I assume the storage-to-house pump is not enabled unless there is a furnace call-for-heat.)


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## warno (Mar 18, 2016)

I understand the natural convection part of the HX to storage idea but I'm confused about the aquastat to run the pump through that loop. When should the pump kick on or off? When the water temp in the return to HX is to warm it kicks pump off or the opposite?

Moving the storage to house pump to the house I  thought would be ideal from a wiring stand point but I figured that would cause too much line on the suction side of the pump. I figured that might cause issues which is why I drew it in the garage. Is it because it's in a closed loop that it will be fine once it's primed? And yes the storage to house will only run with a call for heat.

I have read about the outdoor reset but I'm confused how they work. Could I get a layman's explanation on them? Please and thank you.


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## ewdudley (Mar 18, 2016)

warno said:


> I understand the natural convection part of the HX to storage idea but I'm confused about the aquastat to run the pump through that loop. When should the pump kick on or off? When the water temp in the return to HX is to warm it kicks pump off or the opposite?


The convection is just to make sure the sensor can see how hot the top of the HX is getting, even if the pump is not pumping.

You don't want the HX-to-storage pump running constantly or else storage will start not-so-hot and will only get good-and-hot at the end of the burn cycle.  

When the HX gets hot the pump should run a for a short while and should shut off when the water from the HX cools off a little.  This way only hot water goes to the top of storage and you will have hot water available for the water-air-HX, which is important in your design.


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## ewdudley (Mar 18, 2016)

warno said:


> Moving the storage to house pump to the house I thought would be ideal from a wiring stand point but I figured that would cause too much line on the suction side of the pump. I figured that might cause issues which is why I drew it in the garage. Is it because it's in a closed loop that it will be fine once it's primed?


Right.  In a closed loop it doesn't matter where the pump is as long as you're not in a situation where "pumping away" is important.  What is the elevation change from storage to where the pump would be if it was in the house?


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## warno (Mar 18, 2016)

ewdudley said:


> Right.  In a closed loop it doesn't matter where the pump is as long as you're not in a situation where "pumping away" is important.  What is the elevation change from storage to where the pump would be if it was in the house?



The plumbing to house will go up the garage wall from the manifold about 2-3 feet Then across the ceiling and drop to the underground line which will be 30" below grade and then it will raise slightly to about 24" below grade in the crawl space. So about 5-6 feet below the supply manifold.


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## warno (Mar 18, 2016)

ewdudley said:


> The convection is just to make sure the sensor can see how hot the top of the HX is getting, even if the pump is not pumping.
> 
> You don't want the HX-to-storage pump running constantly or else storage will start not-so-hot and will only get good-and-hot at the end of the burn cycle.
> 
> When the HX gets hot the pump should run a for a short while and should shut off when the water from the HX cools off a little.  This way only hot water goes to the top of storage and you will have hot water available for the water-air-HX, which is important in your design.



I had to reread it but that makes sense. So put the sensor on the upper line from HX to storage and set the aquastat to cool mode so when it reads hot temps leaving the HX it will pump cool "lower" tank water to cool things down then it goes back to convection mode when it cools down.


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## warno (Mar 20, 2016)

I've posted this same question on another site and someone said that a plate HX may not thermosiphon water. It got me alittle worried about running it that way. It makes sense to not mix the tank water as much as possible but will the HX pull water through just fine convection style.


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## maple1 (Mar 20, 2016)

Checked out your drawing in post 53.

The idea of the convection out of the HX (I think) is that it will just convect enough to let the pump control see the heat, and react to it. It likely won't convect much more than that, or won't convect much heat to storage - so the 'other site' feedback on that was right, it won't convect so much that you won't need to pump. As long as there is some uphill slope to it exiting the HX. Like maybe vertical out of it for a short bit to get to & past the pump control sensor, then it can go wherever.

Re. the rest of the drawing - my instinct would likely be to T the expansion tank,  in between the HX outlet & the pump inlet. And not the top of tanks. You could put some air vents on top of the tanks to bleed trapped air out. Or just some ball valves you could manually let some air out with. And delete the airtrol. As long as the expansion tank is high up, you shouldn't have air issues since there is no boiler in the sealed part of the system. The higher the better - and maybe also better if you could get it quite far removed from where it is T'd in at to increase the distance air would need to migrate to get from the expansion tank to the system. Like the other side of the garage. As long as the plumbing rises up to it and doesn't have low loops in it. I used an ordinary LP tank for expansion for the first 3 years, sitting on the floor right beside storage. It did OK but did slowly let air into my system over time, I usually needed to bleed one of my zones a couple times a winter, it would airlock. I would still be using that tank if I could have found a high place to put it.

And on the manifold thing - my system has 2 manifolds, supply & return. So my instinct there would be to use 2 manifolds rather than one. And I have just one zone pump, in the house, mounted down low after the return manifold - one dp pump (Alpha) for all of my 5 zones, using the dp pump lets me throttle down my zone flows - the pump will slow itself down to match. The pump will start when any of the zone valves open. And I think with an Alpha, you don't even need to wire it to controls - you can just plug it into a wall outlet and it will sense a zone valve opening and ramp itself up. But I haven't tried that with mine, not sure how good it works in practice. And a big but - a dT pump might work better anyway as you were planning, I have no experience with those either.

Otherwise, what I saw there looks not too bad. From my non-pro & limited experienced view. Which also means that I might have missed something or be out to lunch on something I just said.


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## warno (Mar 20, 2016)

With the expansion on a T fitting will the air flow into the top of the T on its own or will I need an air scoop there? Is it really as simple as a T fitting and nothing else, the pump won't drag air through the fitting?

Everyone keeps saying I shouldn't go with the delta T pump for the storage to house pump. Am I just not understanding what those are for? I was only thinking the delta T would control my return to storage temps to try keeping them as warm as possible.

I just looked through the manual again on the pump I was thinking for storage to house.  It says it has setpoint features as well so will this pump work for this location? 

Here it is

http://www.supplyhouse.com/Taco-VT2...iciency-Circulator-Less-Flanges-Standard-120V


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## maple1 (Mar 20, 2016)

I have no experience with dT pumps so will let someone else answer that one. I do remember some past conversations on whether or not they really did certain things they were advertised to do or not.

There should be no air flowing in your system, or to/from expansion. Only water. As long as it's commissioned properly. Way I did mine, more or less: install a ball valve to isolate expansion from the system, mine was just on the expansion side of the T. (Should also have a drain valve on the expansion tank in case you need to drain it, and a snifter valve on top, & pressure gauge). Before you hook up the expansion tank, close the isolation valve and fill the rest of the system & storage with water (cold fill) to your cold fill psi level (mine was around 8 psi +/-, depends on elevation difference to top of rest of system i.e. in the house). Attach the empty expansion tank. Charge it with air to a couple psi less than the system water pressure. Open the isolation valve. Water will flow up the pipe and ideally into the expansion tank just a bit, until the pressure equalize. Since the system is cold, that is theoretically as close as the air will get to the rest of the system. Then when you heat the system up, more water will flow into expansion - then when it cools off again, water will flow out of expansion but shouldn't drop below the point where it was when cold. It is likely a good idea though to make the expansion tank lots bigger than it 'needs to be' to make sure pressures don't get too high when hot, but also if it's big enough, you don't need to charge it with air - if no precharge, when you open the isolation valve more water will flow into expansion & get the air further away from the system. So to speak. And there will be less chance of air migrating back into the system. Air vents at high points should be good to let air out - tops of storage tanks would be a good spot, air would likely gather there. And piping high spots - any up-down loop can trap air at the top of it and cause an airlock. But also, air trapped at the tops of your storage tank could also serve as additional expansion - as long as the air level didn't get down to the point where it would get into piping. I had that happen to me too once - so I check for air once in a while on top & let it out if there is some there. I haven't had any for quite a while, I swapped out my floor LP expansion tank for a bladder one this fall and that pretty well took care of any air issues.


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## warno (Mar 20, 2016)

I'm planning on an expansion tank of somewhere between 25-40 gallons. 

So no air scoops are needed on that T to the expansion? I plan to power prime all the loops when I fill the system so there shouldn't be any air moving around but if some does get in the line will it eventually get picked up into the expansion or bled out the air vents?

As far as a pressure gauge in the system, can it go anywhere or does it go on the expansion tank?


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## maple1 (Mar 20, 2016)

They can go anywhere. I think I've got 6 of them scattered around mine. A separate one on the high/air side of expansion will be good for the precharge thing. My 110 gallon expansion was lots for my 660 gallons of storage, likely close to 700 total system.


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## warno (Mar 20, 2016)

Would it be ok to header the storage tank tops together and slope them up towards a single automatic air vent?


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## biothermic (Mar 26, 2016)

warno said:


> Any other advice for me on the new drawing in post 53?



...just a couple quick notes.  You only need to connect your expansion tank to one point in the system (assuming you are using a conventional bladder type expansion tank).  Also, although delta-T pumps are excellent, the pump in your design seems to be redundant.  If you choose to keep it you will need to make sure that it only switches on during a call for heat.

I would also avoid vertical piping into your buffer tanks.  Even with some kind of flow diffuser you may find it detrimental to thermal stratification in the tanks.

Just some general advice.  I hope it helps.


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## maple1 (Mar 26, 2016)

I'm not seeing the pump redundancy?

There may be times where you would be heating storage from boiler and the loads weren't calling for heat, and there may be times the loads are calling for heat & your boiler isn't moving heat.


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## warno (Mar 27, 2016)

I'm planning on doing a new drawing with the things changed and will be asking for advice on that drawing.


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## warno (Mar 28, 2016)

I'm currently redoing my drawing and have a quick question. Referencing my latest drawing, should my "HX to storage" loop be on its own manifold or will a single set of manifolds on my tanks be ok to charge storage and run to heat loads?


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