Prior to servicing any Watts valve, it is mandatory to shut down the water system by closing both the inlet and outlet shutoff valves.

When the temperature control knob to set a temperature, hot and cold water mixing valve through proportional control into the outlet, the outlet temperature is always constant.

Note: the inlet hot supply is to be connected to the "h" side of the valve, the cold supply side to the "c" side and the mixed water outlet to the "m" side.