adlertom
Silver Member
- Joined
- Aug 17, 2004
- Messages
- 185
- Location
- Southern Wisconsin
- Tractor
- New Holland TC33DA hydro w/supersteer
I have an outdoor wood burning furnace that provides heat for my house. I want to expand the system to also heat my domestic hot water.
I have a 50 gallon propane water heater, and constructed a heat exchanger that transfers heat from the woodburner water loop to the heater tank via thermal siphoning. It works VERY well, which is actually what concerns me.
The temperature of the water in my woodburner water loop is about 180 F. I can get the temperature of the water in the heater tank to within a few degrees of that. Is that too hot for my water heater tank? The relief valve on the tank is rated at 150 PSI and 210 F, so I'm below that, but how accurate are those things anyway? Am I running a risk of popping the relief valve?
I also wonder about the high temperature cutoff in the regulator itself. I can't find any documentation of what mine is set for. It's a Robertshaw propane regulator, and have read that these don't self reset once they trip. So, I want to avoid activating that safety device by having the water in the tank too hot.
I'll be using a tempering valve to keep the water going to the faucets at a safe temperature. That doesn't concern me. The effect of the higher temperature on the water heater itself is what I'd like to know.
I've also read about magnesium and other minerals coming out of solution in the tank if the temperature is above 140 F. I guess I'm willing to sacrifice some tank life if I save on energy costs, but would like to know how significant this problem really is.
Thanks,
Tom
I have a 50 gallon propane water heater, and constructed a heat exchanger that transfers heat from the woodburner water loop to the heater tank via thermal siphoning. It works VERY well, which is actually what concerns me.
The temperature of the water in my woodburner water loop is about 180 F. I can get the temperature of the water in the heater tank to within a few degrees of that. Is that too hot for my water heater tank? The relief valve on the tank is rated at 150 PSI and 210 F, so I'm below that, but how accurate are those things anyway? Am I running a risk of popping the relief valve?
I also wonder about the high temperature cutoff in the regulator itself. I can't find any documentation of what mine is set for. It's a Robertshaw propane regulator, and have read that these don't self reset once they trip. So, I want to avoid activating that safety device by having the water in the tank too hot.
I'll be using a tempering valve to keep the water going to the faucets at a safe temperature. That doesn't concern me. The effect of the higher temperature on the water heater itself is what I'd like to know.
I've also read about magnesium and other minerals coming out of solution in the tank if the temperature is above 140 F. I guess I'm willing to sacrifice some tank life if I save on energy costs, but would like to know how significant this problem really is.
Thanks,
Tom