Woodstoves revisited

JimR · Sep 8, 2005

Does anyone know of a tank that can be mounted on top of a woodstove and hooked into a forced hot water system? I am going to hook my woodstove back up. What I want to do is mount a flat tank of some sort on top of the stove. Put a circulator pump inline with the tank and heating system using some type of temp control to operate the pump. I'm not supporting the oil companies this winter of any future years if I can help it. I think the tank unit would be much more efficient than trying to heat my 2 story house with a woodstove. I know for a fact that I use less oil now than what I did before I added the second floor on. I did heat my entire house with this same woodstove before the second floor addition was added. Would the water flow without a circulator pump if I had the top pipe going up and the lower pipe coming in from the bottom of the boiler as in heat rises?

Junkman · Sep 8, 2005

I would consider installing a iron pipe through the wood stove and a circulation pump hooked into that. You can then have the circulation pump on a thermostat so when the water is hot, it will circulate, but if the stove goes out, it will shut down. How you will regulate the water temperature is going to be the real problem, since there is no easy way to regulate the wood temperature if you also are using it for space heating. Possibly adding a radiator to the garage to bleed off some extra BTU's????? I would use schedule 80 black iron pipe. You can get it at Manoogs, Piedmont Street, Worcester, MA. The pipe shop there will cut it to your specifications and also thread it. While you are there, you can visit The American Sanitary Plumbing Museum.

Egon · Sep 9, 2005

I can recall heating a hot water tank via a cast iron water jacket insert in the firebox of a wood/coal cook stove. There was no circulating pump.

If you do use a home built water circulating system insure that there is a header tank open to atmosphere at the very top of the system or have a PSV valve of proper size included in the system.

Maybe look at a commercial hot water system to see how they operate and what components they have.

Good luck on the project.

Where we live everything would have to be CSA certified.

Egon

tawilson · Sep 9, 2005

On the high fuel prices, what to do thread, I've been talking about the wood boiler I'm building. I'm planning on using a cast iron radiator as the water jacket. Possibly you could do the same. Are you tying into an existing system, or creating your own? However, after reading your post again, if you already have a woodstove in your lower level, you might save a lot of hassle by just using it as is and using a fan or two. If you have a forced air system for primary heat, maybe use the summer fan option to circulate your heat. I'm no expert on wood heat, but I know a lot of people will be using it this winter that haven't in a while, and I always recommend getting their chimney checked out first.

PhilNH5 · Sep 9, 2005

Jim,
Lehman's, a sort of Amish Hardware store has a few options
at this Link
If you browse around they also sell a booklet explaining how to do this.

Phil

hazmat · Sep 9, 2005

Sometimes the engineer in me gets out of hand... /forums/images/graemlins/blush.gif I have to remember that just because you can, doesn't always mean you should....

I'm not sure how your home is layed out & where the stove is located (central, on the end etc.) or what your second floor looks like. You may be better off adding another wood stove or just using oil to heat the second story than trying to rig up your home-brew heating system.

Wood stoves are space heaters - not water heaters. Chances are good that your design will take a few revisions before it functions to your satisfaction - after which you may have spent more time & money than you will have saved yourself. Will your insurance company pay a claim if you have a fire? It could be unrelated to your modifications, but they are always looking for ways to not pay...

Just something to consider... Who knows you could be the exception to the rule that gets it right the first time. /forums/images/graemlins/laugh.gif

JimR · Sep 9, 2005

I'll try to answer all the question asked in one reply. I presently have a forced hot water system running 5 circulators for my heat and hot water tank. The boiler is one of the newer small units and is in the basement at one end of the house. Our house is a two story Garrison Colonial now. It use to be a ranch house till we got this wild idea of raisng the roof as the kids were getting bigger. The stove is also situated at that end of the house. My chimney flues are is in excellent condition. We built a new chimney when we added on. I'll check out the link provided and see what they have available. I can in fact shut down the first floor heat by simply disconnecting a wire on the circulator motor for that floor. My insurance company knows we have a woodstove in use in our house. Our system also has a blow off pressure valve for relieving high pressure should the woodstove work too well for the job. I also have a regulated "water in" line hooked to our system. The black iron pipe suggestion is a good one Junkman. Unfortunately my stove has a double liner and would be very hard to install pipes in it. I have a blower system on my stove. The fan works great at heating just the basement. I've found that leaving the blower off works better. The heat rises much faster at one end of the basement. It then goes up through a custom cellar door that I have made using hot air furnace filters. This keeps the dust downstairs. My return for the first floor is at the other end of the house. I will keep you posted as to what I figure out and if it works. We need to stick it too the oil companies big time. As for having two stoves in the house. I also have a fireplace on the first floor in the livingroom. I was thinking of maybe getting an insert for the fireplace. But then I would have to take care of 2 woodstoves here and one in the old farm house. I would be spending most of my time feeding a fire. I don't want to do that. My Nashua stove that I have in my house will do a 6-8 hour burn with the right wood and put out a lot of heat. My livingroom use to be at 80-85 degrees during the middle of winter when I had the stove under that floor. Our kitchen was at 75+. The other end of the house was at 70 degrees. I couldn't run the stove for long if the temperature was above 45 degrees outside when I only had one floor. It would cook us out of the house. The snow around our house in the winter was melted 10 inches away from the foundation when I had this stove running.

hazmat · Sep 9, 2005

I'd think you'd do "better" with the insert. By "better" I mean you will use less wood to reach the same temperature in the first floor.

Wood stoves are radiant heaters. Your basement stove is radiantly heating the first floor joists etc which in turn is heating the air in your home. It is more efficient to put a radiant heater in the room you are trying to heat - the convection heating (air flow) doesn't kick in untill the stove has warmed up the structure.

My insurance comment was related to your "modifications" to the stove - say you get a chimney fire - ins. co won't want to pay because you've changed the stove, it is no longer "UL listed"...

Panache · Sep 9, 2005

What about one of the wood furnaces that are a small seperate building outside?

MossRoad · Sep 9, 2005

That's what I was thinking... if he already has hot water heat in his home, he just needs a different way to heat it than with oil. The outdoor water furnaces should easily adapt into this system. Plus, it should address any insurance issues related to fireplaces and indoor wood burners. Downside... he already has a wood stove and would have to shell out $$$ for a new outdoor water furnace.