Would this be worth the effort

[zojo]

Hi guys. Great site here, I have been browsing for some time thanks to all for the incredible insight.

I am considering a new system to heat dhw, and wondering if I could get some feedback as far as effectivness and fesability. I have an old Hearthstone II stove with 8" exhaust. It emits out the top makes an immediate 90, goes 4' back to the wall penetration, and into the chimney. The chimney is about 40' tall and has excellent draw, so although not ideal, it has been working for about the last three years great. What I am considering is wrapping the horizontal run with about 20' of 1/2" flexible copper and looping that to the water heater tank I have. It will need to be a pumped loop, controled with an aquastat, and have the necessary relief valves on it. Any opinions or advice would be most welcome.

Thanks to all.

 

[Singed Eyebrows]

The problems I see are an approx. 400 degree flue pipe & a copper coil with a very minimal amount of water in it(safety hazard). Second, if you don't braze the copper to the flue pipe I don't think you will get a lot of continuous btu's. I understand you will use a relief valve this would still be a bit scarry for me. You can weld up a firetube boiler that will go in a section of the horizontal run that you would cut out. This is easy enough. You would need to very carefull about cleaning it out though so you didn't block the flue gasses. I would not use a water tube boiler design. Randy Welcome to Hearth!

 

[stee6043]

I think if you mill around this site for a while you'll see some very similar ideas shared. At the end of the day - typically - this ends up not being a particularly effective/safe way to heat your DHW.

 

[woodsmaster]

With that tall of a chiminey I dont think you want to cool your flu gas off any or it probably will condensate on chiminey walls and cause a creasote problem.