Boiler piping and components

[Old Timberguy]

Fellow experts and enthusiasts:

I have enjoyed reading and following many of your forums for the last several years. For a long while I have wanted to set up a wood boiler and other components much like the systems I’ve been reading about. I became aware very early on that this can be an expensive undertaking, far beyond my meager and humble income would permit. Therefore I have been scrounging and collecting components from wherever and however I could. I’m finally to the point where I need to put this system together. As it’s said that a picture is worth a thousand words, I’ve made a simplified sketch to show my plan. My hope is that some of you will review the sketch with a critical eye, and point out errors that I may have missed. Other than the zone valves and the ECM circulator, I’m good to go.

It’s probably important to state what my expectations are and how I see the whole system functioning for me. I have a woodworking shop that is very well insulated, with an insulated slab and four 250’ runs of ½” Pex. I also have a furnace coil and blower assembly which will supplement the slab heat when called upon. Then finally I have an Amtrol indirect water heater, which will be placed in series before my domestic hot water. My hope is that I can fire the boiler a couple nights a week to maintain the workshop at 50 degrees through the week, and then fire it more consistently on the weekends when I want to use the shop. I only expect the furnace coil to be called upon for bringing the weekend temp up to 65 degrees. The indirect water heater will only engage when the boiler is fired, the remaining time it will serve as a tempering tank. The 500 gallon pressurized storage tank will retain all unused heat from any of the boiler firings. Since the slab heat requires a much lower temperature, I expect to be able to draw many of the potentially lost BTU's from storage tank. I was unsure about using a delta t or p system circulator. It seemed as though the pressure compensating circuitry would be a better choice with the low temp storage potential???

Feel free to be brutal, my feelings aren’t easily hurt, and I’d like it to work first try. Thanks, Rick

 

[leon]

Fellow experts and enthusiasts:

I have enjoyed reading and following many of your forums for the last several years. For a long while I have wanted to set up a wood boiler and other components much like the systems I’ve been reading about. I became aware very early on that this can be an expensive undertaking, far beyond my meager and humble income would permit. Therefore I have been scrounging and collecting components from wherever and however I could. I’m finally to the point where I need to put this system together. As it’s said that a picture is worth a thousand words, I’ve made a simplified sketch to show my plan. My hope is that some of you will review the sketch with a critical eye, and point out errors that I may have missed. Other than the zone valves and the ECM circulator, I’m good to go.

It’s probably important to state what my expectations are and how I see the whole system functioning for me. I have a woodworking shop that is very well insulated, with an insulated slab and four 250’ runs of ½” Pex. I also have a furnace coil and blower assembly which will supplement the slab heat when called upon. Then finally I have an Amtrol indirect water heater, which will be placed in series before my domestic hot water. My hope is that I can fire the boiler a couple nights a week to maintain the workshop at 50 degrees through the week, and then fire it more consistently on the weekends when I want to use the shop. I only expect the furnace coil to be called upon for bringing the weekend temp up to 65 degrees. The indirect water heater will only engage when the boiler is fired, the remaining time it will serve as a tempering tank. The 500 gallon pressurized storage tank will retain all unused heat from any of the boiler firings. Since the slab heat requires a much lower temperature, I expect to be able to draw many of the potentially lost BTU's from storage tank. I was unsure about using a delta t or p system circulator. It seemed as though the pressure compensating circuitry would be a better choice with the low temp storage potential???

Feel free to be brutal, my feelings aren’t easily hurt, and I’d like it to work first try. Thanks, Rick

A couple of things:

Heat rises, hot water does not unless its pumped. Why are you not tapping off the top of the 500 gallon tank?, your defeating yourself, you should not do it that way.

Is the 500 gallon tank a new tank?, other wise your looking at at least 2K dollars if not more.


Why two circulators when you only need one? (if its plumbed right).

Your circulator, IAS(B+G in line air separator) and your steel expansion tank need to be above the boiler so you can pump away from the boiler and the expansion tank to reduce any air bubbles to almost zero percent.

The cooler return water needs to enter the boiler sump tapping and it will rise to the top of the boiler to be pulled out and the IAS and steel expansion tank will remove any microbubbles before its circulated to the rest of the system.

The other thing is where are your drain cocks to bleed air from the circuits/zones???? Your going to have nothing but trouble with air in the diagram you have. You need to bleed air from each circuit one at a time.


1. Invest in a copy of Pumping Away and a copy of Classic Hydronics by Dan Holohan.
You need to read these first.

2. As much as I DESPISE BLADDER TANKS: where is your air scoop???
If you have not bought a bladder tank yet, don't, invest in a 30 gallon steel expansion tank and an
In line Air Separator, an Airtrol valve and hang it in the ceiling and you will have no air bubbles.

You will need to insulate the steel expansion tank with fiberglass insulation and then secure it with chicken wire.

Your making a lot more work for yourself with your current plumbing diagram.


Please invest in those books I told you about. They are paper backs and very well written for
the layperson and plumber alike before you make anymore costly mistakes.

 

[maple1]

Couple quickies.

You'll need a separate pump for the in floor, the water needs to be pulled or pushed thru the loops and the mixer bypass loop. As drawn, it won't mix.

Get the storage tappings as close to the top & bottom of the tank as you can.

Maybe move the dp pump to the return line, between the expansion tie in T and the bottom storage tapping.

 

[BoilerMan]

You could also t in the expansion tank into the drain tapping of the storage tank and leave the main circ where it is. That way you will always be pumping away with either the boiler or main circ. All you need is 1/2 inch pipe to the expansion tank. I will also second maple's comment on a third circ needed for the radiant. Pump away from the mixing valve into the slab for best operation. A 0015 3speed is a good choice or 15_58.

You will need a total of 3 circs for your setup, you have a good layout, as suggested pipe the supply and return at the top and bottom of the tank to take advantage of the whole volume of your storage.

TS

 

[huffdawg]

A couple of things:

Heat rises, hot water does not unless its pumped. Why are you not tapping off the top of the 500 gallon tank?, your defeating yourself, you should not do it that way.

 

[huffdawg]

If your going to go with another pump for radiant . Would it not be a good idea to have it pulling and returning to the bottom of storage or at least the bottom half of storage? I use only a 110f water for my radiant , might get a lot better stratification if not drawing the hottest water from the top and sending what you don't use to the bottom. Someone correct me if I'm wrong .

Huff

 

[jebatty]

Not shown, but probably planned anyway, are isolation valves for all components. Also, I recommend plumbing the boiler/storage loop separate from the storage/demand loops. Let the storage also act as a large hydraulic separator. This will eliminate potential problems that can result in boiler overheat/idling depending on the flow rates in the boiler loop and the demand loops. In other words, let your boiler operate only to charge storage, hottest water to the top and coldest return water from the bottom. Let storage operate only to meet demands. You also could have demand supply/return ports in storage at strategic locations to maximize the usefulness of storage, along the idea as already mentioned by huffdawg.

 

[Old Timberguy]

Yikes! I just checked my email, hoping someone had seen my posting. Thanks so much to each of you, there is a lot to digest. The simplified drawing I submitted is not much more than a compilation of what I have gathered from various other members over a couple years. There seems to be a great deal of variety in how others have plumbed these systems. I immediately took the advice to invest in Dan Holohan's book which I should get by Wednesday. I have another of his that I read several times when I owned a couple buildings with steam boilers, he's very engaging. I’ll try to get to the questions and points made.


The 500 gallon tank was salvaged from a nursing home that upgraded its hot water heaters. It’s a Bell and Gossett glass-lined tank rated for 450psi, designed as a storage tank and I'm kind of stuck with the piping locations. There are several other small fittings on the tank but none more strategically located to give good stratification as shown in Huff’s attachment. My drawing doesn’t do it justice but the connection is almost exactly as shown on the third option labeled “better” on Huff’s attachment. I’ll also include the drawing I referred to initially. If I’m reading this correctly, a couple comments are suggesting that I use the lowest and highest fittings, and not to worry about horizontal connections and stratification? I considered the top fitting an ideal location for eliminating air since it is the highest point of the system.


Undoubtedly my biggest question has been the location for the expansion tanks, but almost every example I’ve found shows it on the return line of the distribution loop. I really like the idea of placing it on the drain line of the storage tank, which would to be at the lowest temp and would minimize the need for insulating the bladder tanks? I’ll include the drawings I followed showing this.


I’m also pretty confused about the radiant floor circuit. Wouldn’t the delta p circulator adjust to push the water through the mixing valve? I do get the part about sending so much of the hot flow back into the lower fitting on the storage, which would completely mess up any stratification. I don’t mind using a pump verses the zone valve, but it seems redundant with 2 pumps in the system already??? Other than waiting till I read my new book, any drawings you could direct me too?


Another disadvantage to my compact, simplified schematic is it doesn’t show distance or real world locations. The boiler, storage tank, and bladder tanks are in an outbuilding, the indirect water-heater is 25’ back in the house, and the garage with slab heat and furnace coil/blower assembly is 75’ in the other direction. The piping goes from boiler to house, then on to the garage, one hot and one cold line only. My drawing was greatly influenced by an example of a homerun distribution drawing that I’ll include.


Once again thank you for all the help!

Rick

 

[Old Timberguy]

Yikes! I just checked my email, hoping someone had seen my posting. Thanks so much to each of you, there is a lot to digest. The simplified drawing I submitted is not much more than a compilation of what I have gathered from various other members over a couple years. There seems to be a great deal of variety in how others have plumbed these systems. I immediately took the advice to invest in Dan Holohan's book which I should get by Wednesday. I have another of his that I read several times when I owned a couple buildings with steam boilers, he's very engaging. I’ll try to get to the questions and points made.


The 500 gallon tank was salvaged from a nursing home that upgraded its hot water heaters. It’s a Bell and Gossett glass-lined tank rated for 450psi, designed as a storage tank and I'm kind of stuck with the piping locations. There are several other small fittings on the tank but none more strategically located to give good stratification as shown in Huff’s attachment. My drawing doesn’t do it justice but the connection is almost exactly as shown on the third option labeled “better” on Huff’s attachment. I’ll also include the drawing I referred to initially. If I’m reading this correctly, a couple comments are suggesting that I use the lowest and highest fittings, and not to worry about horizontal connections and stratification? I considered the top fitting an ideal location for eliminating air since it is the highest point of the system.


Undoubtedly my biggest question has been the location for the expansion tanks, but almost every example I’ve found shows it on the return line of the distribution loop. I really like the idea of placing it on the drain line of the storage tank, which would to be at the lowest temp and would minimize the need for insulating the bladder tanks? I’ll include the drawings I followed showing this.


I’m also pretty confused about the radiant floor circuit. Wouldn’t the delta p circulator adjust to push the water through the mixing valve? I do get the part about sending so much of the hot flow back into the lower fitting on the storage, which would completely mess up any stratification. I don’t mind using a pump verses the zone valve, but it seems redundant with 2 pumps in the system already??? Other than waiting till I read my new book, any drawings you could direct me too?


Another disadvantage to my compact, simplified schematic is it doesn’t show distance or real world locations. The boiler, storage tank, and bladder tanks are in an outbuilding, the indirect water-heater is 25’ back in the house, and the garage with slab heat and furnace coil/blower assembly is 75’ in the other direction. The piping goes from boiler to house, then on to the garage, one hot and one cold line only. My drawing was greatly influenced by an example of a homerun distribution drawing that I’ll include.


Once again thank you for all the help!

Rick

 

[Old Timberguy]

Forgive me for my poor computer skills.

 

[maple1]

I’m also pretty confused about the radiant floor circuit. Wouldn’t the delta p circulator adjust to push the water through the mixing valve?

The dP circ will adjust - it will speed up & slow down. But it won't get water from the floor return, into the floor mixing valve the way the first diagram is laid out. You need a circ either between the floor circuit & mixer, on the floor supply leg (mixed leg) that would pull through the mixer from both the hot supply & cold mixing legs, or between the floor circuit & mixer, on the cold return leg, that will also pull through the mixer from both hot supply leg & cold mix leg. As is drawn, that circ cannot move water around the mixing leg - it will only move it right through the mixer via hot supply leg & floor supply leg. It won't mix - and it will be trying to pull water backwards from hot supply, out of the mixing leg. Rather than into the mixing leg. If I explained it right...

 

[Old Timberguy]

I did a little adjusting with an eraser on my piping plan, and then re-sketched it with what I think has been suggested. I moved the expansion tank to the t fitting in the bottom of storage. I removed the zone valve from the floor and substituted a pump pulling away from the mixing valve. I also moved the load or heating circuit pickup to the highest fitting on the tank. This does seem to go against the stratification advice, but hopefully I'm getting closer to a working plan. I think I'm going read my new book by Holohan before asking any more questions and start a new post. Thanks everyone!

 

[ewdudley]

I removed the zone valve from the floor and substituted a pump pulling away from the mixing valve.

Floor zone will be pulling through Alpha when neither of the other two zones is calling. This will work A-OK.

This does seem to go against the stratification advice, but hopefully I'm getting closer to a working plan.

Since you're pulling vertically off the top of the tank you are not going against "stratification advice" whatsoever.
As always, I will note that on the bottom of the tank you are losing about 1/6 of the volume of the tank for heat storage purposes by using the port on the side of the tank. You can recover this volume by using a dip-tube inside the tank that angles down to somewhere near the bottom of the tank.

I moved the expansion tank to the t fitting in the bottom of storage.

It was fine the way it was, the boiler loop pump will not be generating enough pressure drop to matter.

 

[BoilerMan]

If your delta p circ is close to the manifold you can simply t the radiant into the supply line ahead of the circ to avoid pulling through it, but it will work the way it is.

TS

 

[Old Timberguy]

Great suggestion about the dip tube, I had wondered whether there might be some fitting that would allow me to divert the flow from the side internally. Like a compression fitting allowing for 1.5" mp to an internal compression around a 1" copper with a S shape of sorts.

The delta p circ is about 75' and a building away from the.manifold unfortunately. Was I wrong to remove the zone valve when I added the circ for the floor? If either the coil or W.H calls for heat what does the delta p do when it gets to the mixing valve, and there's no demand from the radiant floor? Well I received my books by Holohan, so I've got some homework. Thanks to everyone!

 

[maple1]

If either the coil or W.H calls for heat what does the delta p do when it gets to the mixing valve, and there's no demand from the radiant floor?

I suspect you might get some hot water into your floor.

 

[JohnDolz]

I’m also pretty confused about the radiant floor circuit. Wouldn’t the delta p circulator adjust to push the water through the mixing valve?

The dP circ will adjust - it will speed up & slow down. But it won't get water from the floor return, into the floor mixing valve the way the first diagram is laid out. You need a circ either between the floor circuit & mixer, on the floor supply leg (mixed leg) that would pull through the mixer from both the hot supply & cold mixing legs, or between the floor circuit & mixer, on the cold return leg, that will also pull through the mixer from both hot supply leg & cold mix leg. As is drawn, that circ cannot move water around the mixing leg - it will only move it right through the mixer via hot supply leg & floor supply leg. It won't mix - and it will be trying to pull water backwards from hot supply, out of the mixing leg. Rather than into the mixing leg. If I explained it right...

Maple1 and the others know much more than me but I can tell you that I configured my system to leverage low flow temps via a mixing valve. I worked with my boiler manufacturer that has extensive experience in this and they absolutely say to pull water through the mixing valve. Basically I am just agreeing with what folks are telling

Yikes! I just checked my email, hoping someone had seen my posting. Thanks so much to each of you, there is a lot to digest. The simplified drawing I submitted is not much more than a compilation of what I have gathered from various other members over a couple years. There seems to be a great deal of variety in how others have plumbed these systems. I immediately took the advice to invest in Dan Holohan's book which I should get by Wednesday. I have another of his that I read several times when I owned a couple buildings with steam boilers, he's very engaging. I’ll try to get to the questions and points made.


The 500 gallon tank was salvaged from a nursing home that upgraded its hot water heaters. It’s a Bell and Gossett glass-lined tank rated for 450psi, designed as a storage tank and I'm kind of stuck with the piping locations. There are several other small fittings on the tank but none more strategically located to give good stratification as shown in Huff’s attachment. My drawing doesn’t do it justice but the connection is almost exactly as shown on the third option labeled “better” on Huff’s attachment. I’ll also include the drawing I referred to initially. If I’m reading this correctly, a couple comments are suggesting that I use the lowest and highest fittings, and not to worry about horizontal connections and stratification? I considered the top fitting an ideal location for eliminating air since it is the highest point of the system.


Undoubtedly my biggest question has been the location for the expansion tanks, but almost every example I’ve found shows it on the return line of the distribution loop. I really like the idea of placing it on the drain line of the storage tank, which would to be at the lowest temp and would minimize the need for insulating the bladder tanks? I’ll include the drawings I followed showing this.


I’m also pretty confused about the radiant floor circuit. Wouldn’t the delta p circulator adjust to push the water through the mixing valve? I do get the part about sending so much of the hot flow back into the lower fitting on the storage, which would completely mess up any stratification. I don’t mind using a pump verses the zone valve, but it seems redundant with 2 pumps in the system already??? Other than waiting till I read my new book, any drawings you could direct me too?


Another disadvantage to my compact, simplified schematic is it doesn’t show distance or real world locations. The boiler, storage tank, and bladder tanks are in an outbuilding, the indirect water-heater is 25’ back in the house, and the garage with slab heat and furnace coil/blower assembly is 75’ in the other direction. The piping goes from boiler to house, then on to the garage, one hot and one cold line only. My drawing was greatly influenced by an example of a homerun distribution drawing that I’ll include.


Once again thank you for all the help!

Rick

Maple1 and the others know much more than me but I can tell you that I configured my system to leverage low flow temps via a mixing valve. I worked with my boiler manufacturer that has extensive experience in this and they absolutely say to pull water through the mixing valve. Basically I am just agreeing with what folks are telling you. Good luck and enjoy!