Re: Radiant floor heat from fireplace

[elnav]

In principle this is very similar to the outdoor wood fired boiler system for heating. If you leave the system open at the top you eliminate the risk of excessive heat causing the water to boil and creating steam pressure.This is when it enters the risk aspect. Depending on how effective your heat exchanger is and how much heat it can collect this scheme would work. In our wood boiler systems hot water PEX is used throughout for connecting

Wood fired boilers are placed outdoors because it eliminates th emess of handling wood indoors and the insurance companies much prefer this. People with mortgages must provide insurance naming the mortgage holder as co beneficiary hence the desirability of the outdoor boilers. If insurance is not an issue go for it. Common sense should keep you out of trouble and guide you in assembling a safe durabel system. Eliminate pressuer build up install over heat warning near wood stove and do the layout to avoid air bubbles. If the stove is above the floor but you install the radiant heat radiators it might be a good thing to consider a circulation pump. thermo siphons only work on closed system but this introduces the risk of steam pressure build-up and you still have to contend with vapor locks and air bubbles.

One caution.

Unless you are only dealing with a very small home the indoor wood stove is not likely to deliver enough heat in BTU to properly drive the whole system. This is another reason why most systems use an outdoor boiler. The capacity of these are much higher and you do not have to worry about sustained burns with a forced draft. A normal indoor wood stove is designed to heat by radiant heat direct from the shell and letting air circulation carry heat to adjacent rooms. When you switch to hydronic heat you change the design parameters. Be sure your stove has adequate fire brick lining and solid welded shell construction and mind the flue for creosote buildup.