Indoor wood boiler plumbing questions

[Borjawil]

Indoor wood boiler. New to me. Currently the pump arrow direction pointing towards going into the bottom pipe from the boiler.

It's my understanding you want the pump to pump from the boiler, connected to the pipe at the bottom of the boiler, and the return is the pipe on top of the boiler.

It also has an expansion tank. Where do I want this plumbed at - before or after the pump direction? do I need to do anything to make it work correctly?

 

[Bad LP]

Yes. Pump hot water away from the boiler.

 

[salecker]

pump away from the expansion tank as well,which will be in you hot line from the boiler
Return should be the bottom of the boiler.
Whatever you plumb, hot water rises and cold water falls.The laws of thermodynamics will allays take over.If you plumb against it you will have issues trying to send water where it doesn't want to go.
Which is bad once the power goes out and the pumps quit.
If i was you i would get somebody to look at what you are doing and help with the layout.
I had someone do that and when i was finished building my system ther were zero issues and it's been working flawlessly for 12 years. This is a complete system with storage and a backup boiler built from scratch.

 

[Borjawil]

I read over and over to have the return on the top...maybe that's for outdoor boilers or systems without an expansion tank?

I did find the answer for pumping away from the expansion tank, and to have the arrow on the air scoop facing towards the pump.

Should the pump be at the boiler on the return or supply side? Again I've read to have it at the supply side, pumping away from the boiler.

 

[maple1]

Imo return should go in the bottom. Not in the top. Where did you read that?

 

[Borjawil]

Well my outdoor boiler was labeled with supply on bottom and return on top.

Also common sense tells me trying to force water in the bottom of a container with the weight of all the other water on top would be difficult, where as returning the water to the top, pushes the water down and easier for the water to be pumped from the bottom.

Sounds like im in fact wrong, and don't understand things too well maybe.

EDIT:

Found the manual for my unit. Looks like you are correct. Returns are on the bottom back, supply is on the top. Model is the ekb35 or ekb45 energy king

 

[Borjawil]

Got everything connected correctly. Not getting any flow through my manifold.

Pipe from top of boiler goes up about 1.5ft, 90 degree elbow, 18" of pipe then expansion tank, then pump after that. A hose spigot for filling is connected after the pump. Another section of pipe about 2ft then a 90 degree turn down, and another 90 into my manifold.

Here I have 3 loops that come back around to return manifold. This then connects to a short 6" pipe and a 90 down to my return.

 

[peakbagger]

BTW, do you have thermovar or similar boiler feedwater temperature protection?. This would be a three way valve between the outlet of the boiler and the inlet that speeds up warm up of the boiler. As the boiler temps rise, the valve slowly opens to start water flowing through the rest of the system without shocking the boiler. If there isnt one it can take long time to get the boiler out of the creosote and corrosion zone. No real downsides except for cost and complexity and lots of up side.

 

[maple1]

Got everything connected correctly. Not getting any flow through my manifold.

Pipe from top of boiler goes up about 1.5ft, 90 degree elbow, 18" of pipe then expansion tank, then pump after that. A hose spigot for filling is connected after the pump. Another section of pipe about 2ft then a 90 degree turn down, and another 90 into my manifold.

Here I have 3 loops that come back around to return manifold. This then connects to a short 6" pipe and a 90 down to my return.

Sometimes it's impossible to find a problem without actually being there. Pictures might help. We're pretty in the dark without them. If pump is running and there are no mechanical obstructions (valves, check valves, zone valves etc) usually it's an airlock.

Edit: and also I think the usual way of doing it is fill from the bottom, bleed at the top. Generally speaking.

 

[coaly]

I read over and over to have the return on the top...maybe that's for outdoor boilers or systems without an expansion tank?

I did find the answer for pumping away from the expansion tank, and to have the arrow on the air scoop facing towards the pump.

Should the pump be at the boiler on the return or supply side? Again I've read to have it at the supply side, pumping away from the boiler.

The hot water naturally rises out the top. That is the outlet.

Oxygen separates in boiler ( the little bubbles you see form when boiling water) So the separator and auto vents need to be on the hot side above boiler where air rises before it can be circulated through system. Once in the system, it can form a larger air bubble at the highest point, stopping circulation, where another air vent should be located such as found on the top of radiators.

It was common practice to pump into boiler at return since the lower temperature was better for seals and older circulators. New circulators are fine with the higher temperature on the outlet side. ALWAYS pump away from the expansion tank. It should be tee’d into the hot side with pump after it. This way the circulator decreases pressure on tank side allowing it to empty into system, instead of pump increasing pressure on tank side, pressurizing the tank even more and filling tank. Then you don’t have as much expansion room.

If you are installing domestic hot water coil, you will need flow control valves. They are a resistance in the system that needs the help of circulator to push through. This prevents unwanted heat to slowly circulate through system when not calling for heat. In some cases with multiple zones (multiple circulators) these flow control valves prevent unwanted flow in zones not calling for heat. They have a manual bypass valve built in that you can open in the case of electric failure to allow gravity circulation. In the case of wood stove heating, they can be opened to allow enough flow to keep pipes warm in freezing crawl spaces if needed.

2 basic types of systems, one uses a circulator on each zone with flow control valve on each zone, the other is one large circulator pump and separate zone valves that are controlled by thermostats. The later does not require flow control valves since you don’t get flow when the zone valve is off. My experience is zone valves going bad, or the single circulator dying causing no heat. So I prefer separate circulators, maybe just my preference from a service standpoint.

(Adding second boiler for wood/coal, I plumb in parallel when a hot water coil is in the primary boiler and use low limit on wood/coal boiler to control circulator between boilers. You can only plumb in series when boilers are for heating only, if you are trying to prevent the primary boiler from running.)

 

[Borjawil]

Based on another forums advice, seems it may be an air problem. I will try to bleed the air and return with results.

 

[Borjawil]

Peak bagger - I do not have that. But I don't seem to have an issue getting the boiler up to temp. I'll look into it though.

At this point I have bled the air out of the system while it was cold, holding 10psi.

Fire it up, and continued to bleed system. Barely getting .5-.75 gpm flow based on my manifold meters.

When I used my outdoor boiler with no expansion tank, I was getting 3-4gpm on a smaller pump. Thoughts on this? Also may have been a pump issue. It decided to melt the electrical box presumably from heat. I did bleed it.

 

[salecker]

Boiler protection...
The main reason for it is to protect the boiler from cold water shock.It incresses the life of the boiler.
as mentioned earlier,more pictures please.

 

[maple1]

Peak bagger - I do not have that. But I don't seem to have an issue getting the boiler up to temp. I'll look into it though.

At this point I have bled the air out of the system while it was cold, holding 10psi.

Fire it up, and continued to bleed system. Barely getting .5-.75 gpm flow based on my manifold meters.

When I used my outdoor boiler with no expansion tank, I was getting 3-4gpm on a smaller pump. Thoughts on this? Also may have been a pump issue. It decided to melt the electrical box presumably from heat. I did bleed it.

We don't really have any idea exactly what you are doing or how you're doing it, from the info posted.

 

[Borjawil]

Sorry for the lack of photos. Seems my pump was bad. Replaced with a smaller taco 07 that should work for what I have.

Bled the system by closing valve after return manifold, but before boiler. Connecting garden hose at bottom water drain spigot on back of boiler. Opening drain at return manifold. And turning water flow on to fill and push water out of the drain at return manifold.

I then alternated between the pressure release valve at top of boiler, bleeder at air scoop above the expansion tank, hose spigot at the high point of system after pump, and manifold bleeders.

Once pressure of system was up (boiler cold), I opened valve between boiler and return manifold. I then got it warmed up to about 140 degrees. Before firing I turned off water supply and closed drain at manifold. Then continued to bleed system which didn't really give much air.

Then I opened a loop and manifold bleeders and let it run for about 5-10mins. Closed that loop and opened the next one. Closed that one and opened then next. Then opened the two previously closed. Pressure holds at 10psi.

I can get boiler up to 160, at which point the pump kicks on, and temps drop to 120-140 depending. Flow meters read 3-3.5gpm per loop.


One other question I have is the lever on the bottom that moves the floor of the boiler (above the ash pan) to be angled or flat. Floor is divided into 2-3" width plates. Should the plates be closed (flat, but have openings for air to come up through, or angled for more air flow?

 

[Bad LP]

What the hell is going on with that piping and expansion tank??

I’d shoot myself looking at that everyday. 😂

 

[Borjawil]

Super helpful. Mocking things up to make sure it works correctly. Feel free to be negative else where.

 

[maple1]

No idea about the lever question. Doesnt sound like anything I've seen before.

That smoke pipe looks awfully close to the wall there.

So sounds like it's working?

 

[Borjawil]

Pipe is close. Just mocked up. Picking up proper wall manifold for it, and insulated pipe Wednesday. Hopefully that helps with keeping the heat retained at the boiler.

Main question is what to set my gpm for each loop at. I'm sure it'll vary, but not sure if I should be running 3gpm to not lose as much heat, or slow it down to give more time to heat.

 

[coaly]

Normally keep grates flat. When they need cleaning with very little ash, a quick motion like a bump back and forth cleans ash. If you are gone longer, and ash is thicker you need to rock grates farther with a longer motion. When done place back flat. They may not have a stop and tilt fully to dump. If you move them too far they can jam fresh wood/coal between them. You learn this if they get stuck and need to burn out the pieces stuck between them until you can place back in the flat position again.

 

[maple1]

Where are the loops going? Do you have baseboards? Or something else? Usually a dT thru the boiler of 20° when burning is considered good. I likely wouldn't want it more than that. You also dont want the return temps below 140 for very long. That can create a creosote mess in the boiler.

 

[Borjawil]

No base boards. From the dirt up it's dirt, plastic, 2" foam board, PEX tubing stabled to foam, 4-5" of concrete on top. 1/2" PEX spaced 1' apart, 1' from walls.

Got things running better now, but still not warm in my barn even with 25-35 degree weather. Boiler hits 160, pump kicks on. Boiler hits 180-185 blower kicks off. Blower kicks back on around 160-165. But temp keeps dropping to about 140. Before it heats back up.

Have lines set to 1-1.5gpm. any lower and return lines aren't warm enough.

Barn is insulated. 10 ft to bottom of trusses, about 18ft to peak. No ceiling yet. Have an overhang on two walls with soffit vents. No insulation over the 1' gap between wall and ceiling. No insulation over ridge vent gap.

Should I insulate over these gaps? Seems counter productive for air flow/venting, but I'm not versed in that area.

 

[maple1]

You're trying to heat a barn? How big? In Michigan? Sounds like maybe simply your boiler is too small for the job?

Edit: also, if you are heating a slab, you need a mixing valve so you are only sending maybe 120° max temp water into your slab.

 

[Borjawil]

Mixing valve? This is a closed system. Two manifold - one at each end of the loops. Flow meters to show the GPM through each loop, these are adjustable.

If I were to send 120 degrees into the begining of the loops itd cool down way too much to heat anything. Unless multiple people are wrong, the settings for radiant heating in slabs are said to be 180 at boiler coming back about 160.

Boiler is rated for 3500-4500 if I remember correctly from the manual. Should be plenty.

 

[Highbeam]

Mixing valve? This is a closed system. Two manifold - one at each end of the loops. Flow meters to show the GPM through each loop, these are adjustable.

If I were to send 120 degrees into the begining of the loops itd cool down way too much to heat anything. Unless multiple people are wrong, the settings for radiant heating in slabs are said to be 180 at boiler coming back about 160.

Boiler is rated for 3500-4500 if I remember correctly from the manual. Should be plenty.

Multiple people you asked are wrong, you don’t send water to a slab that hot.