Automotive Air Conditioning Information Forum

That is a Ford / Eaton POA valve.

What are you trying to test?

it's a delco part #15-5193

well, the guy i bought the poa valve from was kind enough to send a second one. it tested the same as the first one, that is it wouldn't hold 30 psi on the low side gauge during the test. seems unlikely that two NOS/NIB valves would be defective. i'm out of ideas.
another shot of the test setup:

So what pressure does it hold at?

it doesn't really hold pressure. it doesn't pass any shop air until it hits about 30 psi. but as the shop air pressure rises the pressure on the low side of the valve rises with it.

So it pops at 30 psi. No air comes out of the compressor suction end that you have open to atmosphere until 30 psi right?

knock on wood, third time seems to be the charm. got the third poa from "The Parts Guy" here in florida and bench tested it this morning. as the pressure passed 30 psi there was the "pop" that some have mentioned and the valve settled down to about 20 psi and maintained that as the pressure from the shop air was increased. the 20 psi was set by the folks at "The Parts Guy" before shipping. why this and not 26 psi as is usually recommended i don't know. i'm going to contact them and find out.

"So it pops at 30 psi. No air comes out of the compressor suction end that you have open to atmosphere until 30 psi right?" there was no "pop" on the first two valves. and they wouldn't maintain the required back pressure when the shop air pressure was increased past 30 psi.

more follow up: i took the advice of a friend that plays with these old systems a lot and re adjusted the valve to 26 psi. went fairly easy, the adjusting screw had enough resistance to turning that tightening the lock nut didn't change the adjustment. got it done in 3 attempts. hopefully, i can now start putting the system back together.

Make sure your low side gauge is zeroed out before you adjust the valve.