Automotive Air Conditioning Information Forum

I'm not an MVAC designer, but I'm guessing that trinary switch settings would depend on the design engineer working on a particular system.

If I recall correctly, trinary switch pressures are typically set to the following limits: Low-pressure cutoff at ~30 PSI; high-pressure cutoff at ~400 PSI ...

Caps designed for a tire valve and for a Mobile Vehicle Air Conditioning system's access ports are different, as are the pressures, which has been correctly pointed out. On an MVAC system, the caps are the primary seals while the Schrader valves are the secondary seals.

The system was installed two years ago and worked OK. I had to remove it to make room for an impact wrench to remove the harmonic balancer.
Understood.


My main concern is the amount of oil that's left in the system.
If I replace the condenser, can I drain the compressor and then flush the ...

Vintage Air suggested to flush the system. I beleive they said this to ensure all of the oil is out of the system before it's recharged.
Okay. Only you know why you installed the Vintage Air system, and then removed everything—a very unusual procedure and a lot of work.

Did you charge and run ...

Unless the compressor disintegrated and shed metallic and plastic debris into the system, there's no need to flush the system unless the hard line that leaked also shed debris. Not likely, though.

If you have a parallel-flow condenser, it can't be flushed in any case. It must be replaced, as does ...

May we have the year, make, and model of your vehicle?

My first guess is that the system is low on refrigerant, causing the evaporator to freeze, and the ice that forms blocks airflow after a while.

Does the blower make a different sound when this happens?

You are a solid 20oz light on refrigerant. I had the same vehicle, 99 Tahoe and it required 64oz.
I agree with Carguychris85 . Every specification that I have says the following: 64 ounces net weight of R-134a, and 11.0 fluid ounces of PAG-150 for an OE Harrison compressor. If you have an under ...

The specifications that I have for your 1999 Chevrolet Tahoe with rear A/C are as follows: 64.0 ounces net weight of R-134a, and 11.0 fluid ounces of oil—PAG-150 for an OEM Harrison compressor, or PAG-46 for an OEM Denso compressor. If the under-hood decal differs, the decal always takes precedence.

In addition to what Cusser said, bear in mind that a properly charged system with front and rear A/C will show pressures that are somewhat higher than vehicles with front-only A/C.

What color was the OT that you installed? It should be yellow (or beige) and white—0.062" orifice—with a single black ...

I agree with you. According to the sticker, this system was originally designed to use 900 grams (31.7 ounces net weight) of refrigerant, so that's how much the shop should have installed. The refrigerant amount must be correct for the system to cool properly and for the oil to circulate to ...