Pump down

[skyboy6142]

Hi guys,

Do we have any limitation about pumping down screw or scroll compressors ? Or same as reciprocation compressors we can pump down cycles with screw or scroll compressors ?

Thanks.

[RANGER1]

Depending, but some manufacturers say short pump down on say commercial, semi industrial semi hermetic screw compressor.
can cause overheating & failure due to overheating of windings & compressor.
Could get oil build up to due to no flow

[skyboy6142]

Thanks ranger

[Glenn Moore]

Never pump a scroll compressor down below 0.5 Bar or better still 1 Bar, as the pressure get close to a vacuum , the scrolls get pulled together and rotating scroll starts to run the fixed scroll . As the pressure goes lower the scrolls are sucked into each other as it pulls a vacuum causing metallic particles to break from the scrolls leading to over heating and scroll breakages