Help on installing an almost completely new AC system

[cperk]

To an HVACR tech -29 means nothing as it's microns we read. You'll likely not have any issues with the vacuum you pulled so put some 134a in and let er rip.

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Yes microns is the ticket! Pag oils and poe oils have made this hard to achieve because they retain refrigerant. The minuscule boiling off of the refrigerant make it hard to do a micron vacuum test on anything with pag or poe oil.


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[Snowcamo]

Yes microns is the ticket! Pag oils and poe oils have made this hard to achieve because they retain refrigerant. The minuscule boiling off of the refrigerant make it hard to do a micron vacuum test on anything with pag or poe oil.


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Now we're taking!!! Yeah it's one of those leave the vac running while the oil degasses. Couple hours later and you might be at 500 or close. A lot of times folks think they have a leak but it's just the oil has picked up moisture and the system needs to be recovered and recharged. Unfortunately first thing folks do is charge it up. Blowing the front seal.

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[Snowcamo]

Just to give an idea refrigerant oil degassing resembles an unopened Sprite shaken once or twice.

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[njs2247]

Well, the job is done and my AC is working again. However, I ended having to take it to an auto shop to add the refrigerant because I ran in to a problem when I was pulling a vacuum with the second pump I rented.

 

When I was pulling a vacuum with the second one, the rubberized portion of the low pressure line kept collapsing. Also, when trying to add the freon, the compressor wouldn't take it in. Only liquid freon was showing in the looking glass of the AC gauges.

So I quickly stopped everything because I didn't want the compressor to sludge up down the road. 

 

Anyway, took it auto shop and they pulled a vacuum and recharged the system for me. Even the guy doing the job couldn't explain why the line was collapsing on itself. Anyone here have an idea of what causes this and if there's anything I need to keep my out for?

[Snowcamo]

Well, the job is done and my AC is working again. However, I ended having to take it to an auto shop to add the refrigerant because I ran in to a problem when I was pulling a vacuum with the second pump I rented.
 
When I was pulling a vacuum with the second one, the rubberized portion of the low pressure line kept collapsing. Also, when trying to add the freon, the compressor wouldn't take it in. Only liquid freon was showing in the looking glass of the AC gauges.
So I quickly stopped everything because I didn't want the compressor to sludge up down the road. 
 
Anyway, took it auto shop and they pulled a vacuum and recharged the system for me. Even the guy doing the job couldn't explain why the line was collapsing on itself. Anyone here have an idea of what causes this and if there's anything I need to keep my out for?

It's because mvac isn't setup to hold a vacuum just pressure.

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