Water heater - how hot is too hot?

[adlertom]

I bet he has a lot of available heat from the boiler, and with the right exchanger it could have an acceptable recovery time. and I agree, the heatex, fittings and a on/off thermostatic control valve could probably be had for much less than a tank of fuel.

Thanks to all who provided good advice. I've definitely got adequate heat transfer, just looking for the best way to regulate it.

I'm looking for a simple temperature operated valve that will close at approximately 160F and open below that. I could do it with a motorized valve and aquastat, but would prefer to find a simpler, mechanical valve. One of the earlier posters eluded to something like this being available, but I haven't found it yet.

I've also read about "wax" valves, where the heat expands the enclosed wax and closes the valve, which then opens again as it cools.

 

[charlz]

I'm looking for a simple temperature operated valve that will close at approximately 160F and open below that. I could do it with a motorized valve and aquastat, but would prefer to find a simpler, mechanical valve. One of the earlier posters eluded to something like this being available, but I haven't found it yet.

McMaster-Carr, they start at $450.

 

[RonMar]

McMaster-Carr, they start at $450.

You can probably beat that price a bit using a solenoid operated valve and a thermal switch sensing tank temp. I just did a quick look at the McMastr website and the 2 parts I think would work could be had for around $250. there might be less expensive combinations available there or elsewhere also.