therma-coil Hilkoil Hot water from a wood stove

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Pilgrimfarm

Member
Dec 15, 2010
15
Nc
I have searched this site over for someone who has actually used one of these or similar coils in a wood stove to heat water. However, I did find a dozen+ warnings and speculations about the dangers and cautions of using them. I have also read much info on the net about blowing up stoves when not properly installed with relief valves. I realize steam is a powerful beast when not used properly with drains pressure relief vales and such, and I realize that a water loop will extract some heat from the stove and could cause extra creosote build up. Has anyone actually tried one of these type loops? If so what are the positive and or negative results of your experience? One mfg stated that it will not take enough heat out of "most" stoves to make a difference in how they operate. I would be in favor of more frequent chimney sweeping in order to have a reduced hot water heating bill. It just seems such a waste that all that extra heat is headed up the chimney if some of it could be used to warm water. I have a polaris gas water heater that has a heat exchanger loop inside. If I do decide to do this, I will use a thermosyphon set up where the water exchanger is 10 feet above the wood stove.

Please post if you have had any experience, positive or negative, with adding a water loop to your wood burning stove. Someone earlier suggested these topics be posted to the boiler forum but I wouldn't people with a boiler would need to add a loop to their existing water boiler.

Thanks in advance!
Sean
 
We don't have a coil, but we heat 100% of our water with a stove with the firebox completely surrounded by a thin water jacket. And we have done this for about 20 years. In fact, we have no other water heating source, just the stove. I have never needed to clean out the stovepipe/chimney. We do not burn it full time, only when we want to shower or need hot water for other things. On rare occasions, this includes clothes washing, but I have found that cold water works for clothes 99% of the time so I have come to the point I don't bother with hot or warm water for that unless I have that stove going for showers anyhow.

We are very cautious about not overheating the water and do not allow guests to operate the stove. If someone wants hot water, I take care of it for them.

I have no experience with a coil.
 
If I were to try to preheat water with wood I don't think I would use a stack robber, particularly on a modern stove. Cooling down the exhaust can potentially increase creosote condensation but it can also slow down flue gases affecting draft. And recovery may be disappointing with the lower flue gas temps in an EPA stove. My preference would be to use some of the radiant heat off of the stove body instead. There are purpose built stove like this in Europe and some mods in the US. I would look closer at European systems and designs. And also look at cookstove side-boilers.

Have you visited John Gulland's posting on his modified PE stove? It's a serious modification, even has an oven section, but the hot water part may be helpful. Note that he tried a stack robber and found it didn't contribute much. Here's a link, it's a great read as part of his energy independence move for his office. Quite inspiring.

http://www.gulland.ca/homenergy/stove.htm
 
Thanks for the input. Yes i looked at his site and love that stove he modified/made. In an ideal world and maybe in the future, I will go with a small gasification boiler.
 
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