POA valve test?

[kna4977]

Wanting to test the POA valve. I have the line off the expansion valve. Is it mandatory to disconnect the line from the back of the POA valve or if so is there another place I can disconnect a line to check it? I can’t seem to get it loose there and don’t want to break anything.

[Sheepdip]

The search engine on this forum is your best friend...try it, you'll like it.
https://67-72chevytrucks.com/vboard/...ting+poa+valve

Read this first....https://www.originalair.com/about-poa-valves

[kna4977]

Originally Posted by Sheepdip

The search engine on this forum is your best friend...try it, you'll like it.
https://67-72chevytrucks.com/vboard/...ting+poa+valve

Read this first....https://www.originalair.com/about-poa-valves

Saw that thread thanks. I got it and tested it. It’s still at 30 which is good for R12 but not 134. Watched a couple of videos but they don’t say which way to turn the nut so which way do I turn the 7/32 adjusting nut inside to lower it down to 26-27? Counterclockwise maybe 1/4 turn? Is there a 3/8 locknut as well?

[PbFut]

Has anyone attempted to use a thermostat switch to monitor the evaporator temp and cycle the A6 compressor to avoid freezing? Is cycling a A6 advisable? Looks like Original Air is not rebuilding POA valves anymore and now offering valve and a Thermostat switch. I was under the impression cycling a A6 was not a good idea.

[1970cstblazer]

Originally Posted by PbFut

Has anyone attempted to use a thermostat switch to monitor the evaporator temp and cycle the A6 compressor to avoid freezing? Is cycling a A6 advisable? Looks like Original Air is not rebuilding POA valves anymore and now offering valve and a Thermostat switch. I was under the impression cycling a A6 was not a good idea.

My 1977 LeMans/Trans Am both have cycling A6 compressors, right from GM. That was considered a fuel saving improvement.

[kna4977]

POA valve tested good and I adjusted the pressure down to 27. I'm in the process of charging the A/C system. I've just about got it fully charged. Pressures are great at first and the air from the vents is cool, but as the vehicle heats up and I continue to charge, the pressure on the high side keeps climbing to where I'm not comfortable with it. Between 225 and 250 so I shut it down. Is this an air flow issue or likely something else like a blockage? I do know I currently have an air flow issue which I'm addressing as well just waiting on parts. Has a 4 blade fan and no clutch when it should have a 7 blade and a clutch. I've vacuumed and resealed the system. Has no leaks. I'm about half a can of R134 from a full charge. Temps from the vents don't seem to change, but as pressures seem to rise, the engine seems to struggle more.

[clay68c10]

Try cooling down the condenser with water, like the garden hose. You definitely need a lot of air flow with 134
250psi isn't out of sight with 134, it does run higher pressure on the hi side than R12.
What's your fill amount? Generally you want 80% of the R12 amount as a starting point.
When I converted my POA system in my 68 Cadillac it would run hi side pressures like that at a stop. I added a pusher fan and it helped but I really needed a parallel flow condenser.