View Full Version : Question about vacuuming

23-05-2017, 07:14 PM
Dear Friends,

I have 3 questions below :

1 As I heard triple vacuuming is : evacuate the system, Charge with nitrogen, Change vacuum pump oil and twice evacuate system.
But usually we evacuate system one time with vacuum pump and then stop job and charge system with refrigerant.
Would you please let me know what is advantage of triple vacuuming instead normal vacuuming ?

2 Maybe my question be ridiculous, But I want to know reason.
What is different between vacuum pump oil and for example other industrial oils ? For example when we run out vacuum pump oil why we can't use refrigerant oil inside of vacuum pump ?

3 During a vacuuming progress, I heard two different ideas, Which one is true ?

A - After a while when for example you see vacuum pump gauge is -30 PSI (at cities near sea) it means vacuuming progress finished
B - After a while when for example you see vacuum pump gauge is -30 PSI, You should not stop vacuuming progress and you should leave vacuuming progress alone for couple of hours and let vacuum pump to do its job for hours.

Thanks for your cooperation in topics in advance.

Sincerely yours.

23-05-2017, 10:13 PM
If you perform a search on this forum about your subject question you will find your answers.

E.g. http://www.refrigeration-engineer.com/forums/showthread.php?28555-Triple-Evacuation-with-Nitrogen

24-05-2017, 04:32 AM

in a nutshell on this link