System vacuum

[Zilvinas]

Hello,

I have one question, is there something wrong to vacuum the system below 200 microns if there is oil filled compressor? Couldn't I we damage the oil?

[chemi-cool]

No, actually, any refrigerant left in the oil will boil out. It does good to the oil.

[Zilvinas]

No, actually, any refrigerant left in the oil will boil out. It does good to the oil.
But if we vacuum our new system before the refrigerant filling?

[Glenn Moore]

Pulling a vacuum on the system removes both air and moisture . Oil as new in a system will contain some moisture especially POE oil and during the dehydration process this moisture will be removed from the system prior to the refrigerant being charged. So unless the oil is dehydrated along with the complete system then the system moisture content may be above safe limits for the plant and possible lubrication failure may occur causing the compressor to fail or other system components which could prevent the plant functioning correctly

[Brian_UK]

Also, if possible have yhe crankcase heater active when evacuating the system.

[RANGER1]

http://alltemp.ca/wp-content/uploads/2013/10/JB-Principles-of-Vacuum-Presention.pdf

See page 33 indicates damage to oil at 200 microns or less due to oil vapour pressure.
Says not to go below 500 microns.

[nike123]

Oil as new in a system will contain some moisture especially POE oil and during the dehydration process this moisture will be removed from the system prior to the refrigerant being charged.
Hi Glen! Are you sure that oil could be dehydrated by vacuum drying?
What I fond here on forum, and elsewhere on internet, is opposite to that statement.
Moisture from oil cannot be removed easily by vacuum drying. Moisture and oil has strong molecular bonds.
Moisture in oil could be removed in chemical reaction with desiccant in filter dryer!
That is sum of what I found on that subject.
I think vacuum drying below 200 microns in order to remove moisture from oil is pointless.

[NH3LVR]

Seems to me I learned a long time ago that mineral oil boiled at about 200-250 microns.
Always made me think I was being bull****ed when someone claimed that they pulled a system down to 75 microns. Which a major manufacturer told me they did.
And there was oil in the compressor.
Seems to me that too low a vacuum would redistill the oil into something I might not want.