A/C switch from R12 To R134

[QnecSHO]

Has anyone had any problems with changing over
their systems from R12 to R134??

My 93 ATX had originaly R12 in its system
It was empty when i bought it because of a bad hose. I bought the change over kit and recharged the system with R134. compressor and everything
seemed to work fine. Until i took it to work. On the way the compressor lock up. So i bought a reman compressor and installed it, and also flushed out the system. It locked up just as fast.
Now i'm on my second reman compressor, this time
I changed out the drier and liquid line, reflushed the system and now it is locking up to.
Just wondering if anyone else is having any
of the same problems.

 

[jelloslug]

Your probaly gonna have to physically flush the entire system since you did not change the dryer to begin with, the old dryer may have come apart or you might have too much oil or refridgerant in they system. To do an exceptable change over (I have done several like this with no problems) you must remove as much of the old oil as possable but no less than 50% of it. You also MUST change the dryer, the old dryer is not compatible with the new oil and refridgerant. In some cars you also must change the orifice valve for proper cooling. I have never had to change a compressor or orifice valve from problems from a change over.

 

[projectSHO89]

Maybe this explains it: http://www.ackits.com/blackdeath.htm

Since we don't know your experience level working with auto AC units, it would be helpful if you detailed fully how much refrigerant you used, the type and amount of oil, source of parts used, operating pressures and environments, procedures used, etc...

Likely causes include system contamination, improper charging, no/improper oil used, clogged component, etc

Steve
89

 

[QnecSHO]

thanks for the info and the link.
As far as i know i did what i was supposed to do
i flushed out the condenser and the evaporator
the compressor was a reman from murrays and the drier and oriface tube was from autozone.
3 cans of freon and 8 oz of oil charge.
evacuated the sytem for 30min.
when it was working preasures were at 26 to 45 psi.
the problem is the saftey valve is blowing off.
i dont think the compressor is locking up yet.
Maybee there was still some contaminants
that was still in there. oriface tube might be plugged again.

 

[jelloslug]

The pressure switch is adjustable and might have been misadjusted to make up for a low charge at some time in it life. Unplug the connector and look between the 2 prongs on the connector for a small screw, thats the adjustor screw. This might not fix it but it was the problem on my sister '91 Tempo.

 

[projectSHO89]

the problem is the saftey valve is blowing off.

Gee, that would have been nice to know up front....BTW, what is the "safety valve"?

3 12 oz cans of R134 is too much. Figure 80% of the specified R12 charge for R134. Specified oil quantity probably should be 6 or 7 ounces.

If anything blows off, that means either the pressure is too high due to either an overcharge or an obstruction, or the device is defective or improperly installed.

Steve
89