crank case heater

[amazing azza]

Friends, what is the purpose of the crank case heater exactly? Is it for keeping the oil less viscous in cold weather? Is there other purposes for it? When should it be run? The entire time compressor is off?

 

[Drazen]

Keeps oil from freezing, but also enables start-up in certain cold conditions.

It is triggered by thermostat in winter, and runs when device is off.

 

[chicopee]

One more thing is to separate the refrigerants from oils when dealing with hermetic compressors. Refrigerants do mix with oils when hermetic compressors are idle during winter.

 

[itsmoked]

The coldest point in a system tends to be where all the refrigerant will pile up during off-cycles. A non heated compressor crankcase is often that point. A compressor starting with a crankcase full of liquid is a capital way to mechanically break it. The heater should be ON whenever the compressor is not on. Use a normally closed auxiliary contact on the compressor contactor to run the heater. If the system is rarely used then you need a system to power up the crankcase heater for an hour or more before the compressor ever starts.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[amazing azza]

Thanks guys, very good info. What about in the summer? Should it still be operated the same way? Is there any concern about thermal degradation of the compressor oil?

 

[itsmoked]

Year round. And absolutely no issue with the oil. The heater keeps things very warm - not oil cooking hot.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[chicopee]

In normal installations, the crankcase heaters will always be energized--"just like the pink bunny".

 

[amazing azza]

Got it!