PM valves are pilot operated main valves for regulating pressure and temperature in refrigeration systems.
PM valves can be used on the high and low pressure sides, in wet and dry suction lines, and in liquid lines without phase change (i.e. where no expansion takes place in the valve).
The function of a PM valve depends solely on the pilot pressure applied to the valve, either from pilot valves or in the form of external pilot pressure.
PM 1 has one connection for pilot pressure/pilot valve, while PM 3 has three pilot pressure/pilot valve connections. The associated Danfoss pilot valves can either be screwed directly into the main valve or be connected via an external pilot line.