Dick, great minds and all that--I used the same DN 15 valve to control water flow in my OTR heater. I can see how it would lend itself to the water recycling need although I went with a solenoid valve there. I also used the same thermocouples in my generator over temp shut down system. I found that they took too long to revert to be satisfactory for controlling domestic water temps. For that I went with a digital temp controller (+/_ 1 degree C). Jack