Pump down system

[Eep]

In a refrigeration system which uses pump-down pattern, why not wear on the compressor crankcase heater? But in the system who do not wear
pattern of pump down the compressor crankcase heater must wear an explanation please ....

thanks

[chemi-cool]

In a pump down system, there is not a problem of refrigerant migrate to the compressor sump as liquid. The liquid line and evaporator are empty when the system at rest after reaching the set point. No real reason to keep the oil hot.

When there is no pump down, when the system is at rest, refrigerant flows to the coldest point [ evaporator] and stays there until the next start. After compressor starts to pump, it sucks the refrigerant from the evaporator and large part of it is in liquid phase, if the compressor is cold, the liquid refrigerant will wash the oil out and can brake the discharge valves and piston rods, keeping the oil and compressor hot will help a lot to evaporate the in coming refrigerant and maintain the compressor in one piece.

In a cold ambient, it is recommend to use a crankcase heater in all systems.

[Eep]

OK Thank's......