Leak

johnjohn89

One thing I don’t understand! I saw a lot of people putting vacuum to found the leak Why? when system is leaking refrigerant shouldn’t be putting vacuum right? This will bring system with contamination yea or no?

neilc

vacuum is not to "find" the leak,
but is another way to test for, and determine if leak is present, or confirm not, before charging.
damn hard to detect refrigerant, or see bubbles, under vacuum.

and yeah, when you know a leak is present, you don't want vacuum pulling atmosphere into the system.

vacuum is last check, and to clear the system prior to charging.

johnjohn89

neilc said:

vacuum is not to "find" the leak, but is another way to test for, and determine if leak is present, or confirm not, before charging. damn hard to detect refrigerant, or see bubbles, under vacuum. and yeah, when you know a leak is present, you don't want vacuum pulling atmosphere into the system. vacuum is last check, and to clear the system prior to charging.

Yes

pedmec

yes, you shouldn't be testing for leaks in a vacuum. pulling the system into a vacuum will speed up the moisture and air entering the system. and moisture will eventually kill your compressor. its a horrible practice cause by old school practices passed on.

years ago when i got into the trade i use to hear all kinds of crazy stuff from the old timers, who i respected big time. but they did things that today would be criminal. and i don't mean that from a legal stand point. plus the equipment was not even close to today's standards.

i think a big change that i realized that a lot of guys just didn't buy or believe when it happened was the change from mineral oil to poe oil. the poe is very hydroscopic. it absorbs moisture like crazy and it can't be removed from being a vacuum. it has to be chemically removed (filter-drier). too many systems with poe where left open to atmosphere during a installation or repair.