We installed a Weil-McLain Gold indirect water heater connected to our Oil furnace, circulation pump etc. All is working very well. The tank has a build in termostat to shut off the pump with is working, the only thing is that the hot water keeps circulating even when the termosta shuts off the pump. So the water inside the tank is scalding hot, we put a mixing valve inline and that brings the temperateur down at the faucet but still in the tank it is way to hot and not efficient. I was thinking to put a 120V valve inline controlled but the pump termostat (pump is 120V). Please advise what valve to use or maybe a other way of cotrolling this? Thank, Will

Exact model number?

It is the GOLD PLUS 40, Thanks Will

Is this the unit you are talking about? And how long ago did you install it?

http://www.weil-mclain.com/downloads...bo40manual.pdf

Also did you install a check valve on the piping?