Water Heater Coil

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newguy08

Member
Hearth Supporter
Dec 5, 2008
27
Southern Tier NY
I have noticed some talk of adding a water heating coil to wood stoves and inserts to create a boiler system. How effective is this type of heating? Has anyone installed a heating coil on a lopi?
 
newguy08 said:
I have noticed some talk of adding a water heating coil to wood stoves and inserts to create a boiler system. How effective is this type of heating? Has anyone installed a heating coil on a lopi?

It can be done, but isn't really all that great of an idea with a modern stove....

A modern stove requires high firebox temps to get secondary combustion, a water coil will cool your firebox, and possibly keep you from getting secondary combustion, thereby turning your clean burner into a smoke dragon...

Modifying your stove obviously voids any warranties on it, but arguably more important, will also void any UL and other such approval listings - which might place you in violation of building codes, and will probably also cause problems with your insurance company...

It is VERY dangerous if not done very carefully - One must ensure that there is ALWAYS free flow through the coil when the fire is burning, (especially in case of power failure or other such issues) along with appropriate pressure relief valving, and so on... Otherwise you risk generating steam, leading to the potential for a highly destructive explosion. Essentially this means you must use a "Gravity flow" type setup, which can be hard to arrange in a lot of installs, especially if one wants to make it cosmetically attractive - A tank hanging from the living room ceiling has very low WAF...

You can avoid some of these issues by having a tank that secures to the outside of the stove, or using some other sort of "non-invasive" approach, but it still needs a lot of safety considerations...

There Ain't No Such Thing As A Free Lunch - any heat you get out via the coil is going to be heat that you don't get from the stove directly...

IMHO if you want to go in that direction, I would look for a real purpose designed wood boiler, or a stove that was designed to accomodate such a modification (I don't know of any modern ones in the US) and look for some very expert design advice on setting it up.

Gooserider
 
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