Using add on forced air wood furnace for hot water

[Woodman37]

I have a woodchuck model 4000 and was doing some research on installing a coil for heating domestic hot water? Does anyone here use one of these coils to assist their electric water heater? If so do you like it and was it a pain in the butt to install? I'm trying to cut back on my electric bill. I have 2 kids and a wife so we go through the hot water.. Any input on this would be appriciated.

 

[thecontrolguy]

I have a woodchuck model 4000 and was doing some research on installing a coil for heating domestic hot water? Does anyone here use one of these coils to assist their electric water heater? If so do you like it and was it a pain in the butt to install? I'm trying to cut back on my electric bill. I have 2 kids and a wife so we go through the hot water.. Any input on this would be appriciated.

I am still considering using an hydronic heating coil, mounted on top of the wood furnace to extract heat from the air stream leaving the wood heater plenum. ( I have an RSF-100 in the basement ducted in series with the oil furnace.) This would be mounted in the duct work, and you could pump water through it while the furnace fan was running and the wood burner was making heat. It is designed to give heat to the air stream but just as easily can take heat out. Likely to reduce the direct exposure to firebox temperatures and possibility of making a steam bomb. Good luck.

 

[hobbyheater]

I'm dating myself with this one a little. Into my late teens, our hot water was heated from a coil inside the fire box of our wood cook stove to what was know as range boiler (hot water tank). The water would circulate by gravity from the coil in the stove to the range boiler as a separate loop. There was a separate cold water inlet into the range boiler and hot water outlet to the taps. These range boilers required a temperature relief valve to prevent the build up of steam!
If you were canning or doing a large amount of baking, a hot water tap would have to be left open just a bit or the relief valve would keep going off, scaring the what- ever out of every one.
If the coil is going to be inside the firebox make sure you use every safety valve required.

 

[BoilerMan]

I'd consider a unit heater (has to be all copper for open loop) connected with an aquastat from electric hot water heater to "blow off" heat and prevent steam. Also a good T&P valve or two for double backup!

TS