Off Grid Home Forums Technical Discussion wood burning stove water heater flow rates Re: wood burning stove water heater flow rates


Does the stove have fittings for water pipes? If not you will need to get bosses fitted to your stove.

If stove has facilities for fitting water pipes, does the manufacturer make a back boiler to fit the stove? – If they do, this would be an easier option.

If not, you could find a fabricator (as I have done) to make a rectangular shaped back boiler for your stove. I had it made out of stainless steel – more expensive but much longer lasting than a mild steel back boiler.

A rectangular shaped backboiler would also be a more efficient option since you’d have a larger surface of water jacket exposed to the fire. Therefore you’d need less fuel to heat the tank of water.

With a hot fire you should get a good convection (thermosiphon) established. I do this and never use a pump. When I did try using a water pump I found that the water heated up much more slowly than with a thermosiphon. I haven’t used the pump since.

I also use 28mm diameter pipes and a 28mm diameter coil inside the hot water cylinder. If you used 22mm diameter pipe you’d get more back pressure (due to friction between the water and the pipe walls). It would be more efficient with 28mm pipe.