how does air get into ac system?

johnjohn89

System pressure higher than atmosphere pressure how air get into ac system?

HVACNUT

If your gauge manifold and hoses aren't primed and you add refrigerant, that will introduce air into the system. 
If you're talking about a system that was never touched, then all of a sudden had air, then it either went into a vacuum, or it was there from the beginning. 

ChrisJ

Like @HVACNUT said, guys not purging their hoses / manifold before connecting, or improper dehydrating during installation. Those are probably by far the most common reasons.

There's also systems out there that go below atmosphere on the low side during operation, they can suck air in during operation if there's a leak.

Some refrigerants and oils may break down and produce non-condensables for various reasons as well.

pecmsg

johnjohn89 said:

System pressure higher than atmosphere pressure how air get into ac system?

Improper evacuation procedures.

The refrigerant will always be at a higher pressure then Zero at above 0°F temperatures with a few exceptions! R-11 being one of them. O PSIG @ 75°F

EdTheHeaterMan

I remember hearing about a plumber that would pressure test his linesets before putting refrigerant in the system. And what is every plumbers best friend when pressure testing pipes? Water. It will let you know where the leaks are better than any air or gas pressure test! Y'all can see the water right away.

He had a lot of failed compressors the first few years he started doing air conditioning work. But could not figure out why?!?

johnjohn89

HVACNUT said:

If your gauge manifold and hoses aren't primed and you add refrigerant, that will introduce air into the system. 
If you're talking about a system that was never touched, then all of a sudden had air, then it either went into a vacuum, or it was there from the beginning. 

Great answer! Thank u

johnjohn89

pecmsg said:

System pressure higher than atmosphere pressure how air get into ac system?

Improper evacuation procedures. The refrigerant will always be at a higher pressure then Zero at above 0°F temperatures with a few exceptions! R-11 being one of them. O PSIG @ 75°F

Thank u 🙏!

johnjohn89

ChrisJ said:

Like @HVACNUT said, guys not purging their hoses / manifold before connecting, or improper dehydrating during installation. Those are probably by far the most common reasons. There's also systems out there that go below atmosphere on the low side during operation, they can suck air in during operation if there's a leak. Some refrigerants and oils may break down and produce non-condensables for various reasons as well.

👍 

johnjohn89

@all thank u so much