Screw and pump down

[skyboy6142]

Hi all,

Is it Ok to pump down an A/C system with screw compressor ? Or screw compressors are not same as other compressors in pump down progress ?

Thanks.

[Brian_UK]

More college questions ??

[RANGER1]

Hi all,

Is it Ok to pump down an A/C system with screw compressor ? Or screw compressors are not same as other compressors in pump down progress ?

Thanks.

A lot suggest short pump down to avoid overheating of windings & compressor

[sterl]

Fundamentally you can pump down a screw compressor circuit. Overheating will result if the machine runs for any extended period at low mass flow or in certain odd cases, high suction superheat. Many screw installations have unloading arrangements and a few have variable Vi Arrangements. Left to do what they want to do, those arrangements will retard the pumpdown and cause the conditions of high oil temperature, high discharge temperature, high winding temperature that you do not want to persist. Your discharge pressure control arrangement may also retard a pumpdown.