Automotive Air Conditioning Information Forum (Archives)
Another POA 134a question
rollsdoctor on 
Mon August 13, 2012 7:27 PM 
I have a questionable POA valve from a 1972 Grand Prix that I am converting to 134a. I have replaced all components (except expansion valve and poa) so far. Trying to keep the original look, I thought I might try to reuse the POA on the car. I have no idea if it is the original one, but it sure looks like it. Markings on it are: 2 2272 Frigidaire F0704. I set up the test (described back in 2003 by Impaladan73 and dougflas) with the old evaporator and exp. valve. I put my low side gauge on the valve, as shown and hit it with about 70 psi air. I hear a small amount of air that increases as the gauge rises. I can feel some escaping thru the other end of the POA. A descent amount of air is passing out of the end when the gauge approaches 25 psi. I then get a small "pop" at 25 psi and a minuscule increase of air escaping. The gauge will not rise above 25 psi. I have tried to raise the pressure to 26-27 but it will not go above 25 no matter how much I tighten down (CW) on the 7/32" or 5mm nut. I can get the "pop" to occur at lower psi's by going CCW, but not the other way around tightening. What gives? Am I doing something incorrectly? Or is my valve screwed? Thanks in advance ....and I hope someone sees this...
Dougflas on Mon August 13, 2012 10:24 PM
Are your gauges zero'ed out before you start? Is the low side hose connected to the side port of the POA?
rollsdoctor on Tue August 14, 2012 10:06 AM
I assume it as at zero, but I will check again ... Yes low hose is connected to POA charge valve fitting...
Why is there a "schrader" (looking) valve in the POA liquid bleed line fitting? And when I fit the line from the evap. to it, does it indeed "open" the valve inside? I just thought that was a curious component.
Dougflas on Tue August 14, 2012 11:04 AM
That is a liquid bleed valve. This line has been known to get pluged with oil. That schrader is special so do not mix it with the regular schraders.
rollsdoctor on Tue August 14, 2012 4:19 PM
My low side R12 gauge lost its clear cover a while back so the needle may be askew a degree, but why can't I raise the pressure with the adjustment nut?
JUST CAME BACK ...I just tried again and tightened down about 3/4 of a turn CW and it opened again a degree later at 26 ...but as I left the air in place ...it started to "pop" again pulsing with a "pop" every half second or thereabouts. It kept it up as long as I had air going in. What is that all about?
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