Need help with wood boiler. Ghost heating

BrianIBEW1837

I have installed a heatmor owb that I bought from a friend. I used a everhot tankless water heater as my heat exchanger. I cut a 1 1/4" tee into the supply and return coming out of my existing Buderus oil boiler, and put a Taco 0010 in as my wrap around circulator in the return line to keep the Buderus at temperature. My house has six zones all fed by Taco 007's ifc. The problem I'm having is with ghost heating in every zone. Should I cut check valves into every zone? I was told these would stop the ghost flow better than IFC circulators alone. I also was told that cutting in zone valves with the circulators would fix it. I know the zone valves should do the trick, but thats a expensive fix. Is the 0010 just too big and lifting the ifc's, and the problem would be solved by putting in a 007 instead? I don't know if a 007 would be enough to handle the load if I had multiple zones calling at once. Also, a guy at work told me I should not have tee'd into the existing system like I did. He said to use the holes in the boiler where the pressure relief and the boiler drain are. I used Central Boiler's diagrams for guidance, and the way he was talking was for a depressurized installation. I know this is a long winded post, but I have no plumbing or heating background, so any help would be greatly appreciated.

Zman

Central Boiler

Using Central boilers drawing is the problem. http://www.centralboiler.com/media/CBSystemDiagrams.pdf

If you take some pictures or make a drawing of what you have, we should be able to get you on track.

Carl

BrianIBEW1837

pics of system

will post more pics if needed.

Zman

Ghosting

I am thinking you need to do some repiping. The 0010 or any circ you replace it with,will always want to dump it's excess energy into the zones. Right now it has option 1, into the boiler or option 2, into the zones. The 2 loops should be hydrolicly separated using closely spaced tees or other technique.

Personally, I would not pipe the boiler and the exchanger in series as you have. I would pipe them in parallel like twin boilers are normally piped. Changing this would require some control changes as well.

Carl

 

Ironman

010

Which way is the 010 pumping? I can't tell from the pics.

BrianIBEW1837

0010 direction

The 0010 is pumping from the return manifold to the heat exchanger

BrianIBEW1837

0010 direction

The 0010 is pumping from the return manifold to the heat exchanger

Zman

Boiler

Does the boiler have it's own circulator?

I am trying to see the easiest fix.

Carl

Ironman

Backwards

That's backwards. You should be pulling from the supply, pumping toward the return. Just like any other zone.



That, along with the over-sized 010, may be your problem. Isn't the 010 a 3 speed circ? If so, use low speed.

BrianIBEW1837

010 circulator

The 010 I have seems to be single speed. My boiler does not have its own circulator Carl. I replaced the 010 last night with a 007 I had as a spare, just to see how it performed while the weather was still cold here. I will say it did help with the ghosting, but did not seem to cure it completely. I don't mind repiping to make it right, but would cutting check valves into the zones work?

Steve Whitbeck

piping

The problem is the pump on the wood boiler heat exchange tank is inducing flow in all of the zone loops.

The ( boiler side) pipes off of the heat exchange tank should have BOTH gone to a set of closely spaced Tee's on the return pipe going from the zone manifold to the gas boiler. That way they don't induce flow on the zones and as long as the wood stove can supply enough heat the gas boiler never runs. If you run out of wood the gas boiler takes over automatically as the return temp falls.

Why didn't you use a plate and frame heat exchanger?

BrianIBEW1837

closely spaced tees

Steve I think I understand what your saying, but if I do this do I have to tie my feed and return headers together making a primary loop, Or can I just cut closely spaced tees into the return leaving the setup as is? I used the Everhot tank instead of the plate stye exchanger because after I spray foamed and backfilled the 1 inch pex from the wood boiler, I worried it was not big enough and the guy who helped me size everything said there would be a lot less restriction in the everhot, making the 1 inch pex work adequately.

Steve Whitbeck

piping

Leave the boiler piping the way it is. Just cut another tee into the return line between the boiler and the house return header. Make sure the tee closest to the return manifold goes to the inlet fitting of your heat exchanger tank and the outlet of the tank goes to the tee closest to the boiler. Treat it as if the heat exchanger is another boiler piped in Primary / Secondary. Make sure you keep the pump on the heat exchanger line.

BrianIBEW1837

closely spaced tee's circulator location

Steve, I'm going to try the closely spaced tee's in the return manifold like you mentioned. I agree with Ironman that my circulator set up is backwards at this point. It should be pulling from the source and pushing towards the return like any other circulator. When I repipe should I pull from the outlet of the heat exchanger and push into the tee closest to the Buderus? I don't really understand closely spaced tee's that well. Why wouldn't this setup just induce flow into the return of all my zones? I appreciate all the replys I have received.

Steve Whitbeck

pump

You install the pump pushing toward the point of the most resistance to flow. In this case it is the heat exchanger tank. ( negligible flow resistance)

Put the pump on the line coming from the return manifold and pushing into the tank. ( this will also be cooler water and will help the pump live longer )