AC Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tdangle · 06-05-2017, 04:39 PM

I'm working on getting my AC up and running. Will be changing over to R134. Since the metal portion of the line from the condenser to the expansion valve is cracked, I removed the line and opened up the back output of the POA valve. I applied 60 PSI of air to the input of the expansion valve and with a gauge hooked up to the low side connector (on the POA) it opens at 27 psi. Should be 29, correct? Am I doing something wrong?

Air is going thru the expansion valve then thru the evaporator and then to the POA valve. I think this is the correct setup.

demian5 · 06-05-2017, 05:46 PM

When AC pressures are in the 100s, does 2 psi matter?

tdangle · 06-05-2017, 05:58 PM

Quote:

Originally Posted by demian5

When AC pressures are in the 100s, does 2 psi matter?

I agree but everything I have researched says R12 POA is adjusted to 29 and R134 requires 27 psi. I know this one has not been converted to R134 (Parents were original owner). Now I'm thinking, Nice already calibrated for what I need.

**leddzepp** · 06-05-2017, 07:26 PM

Good luck with your conversion. If you have factory AC it will NOT work anywhere near as good as with r-12. I'm restoring the factory AC on my truck and will be using r-12. I've done this enough times to know better now

As soon as it gets into the 90s here your AC won't work with r-134...ask me how I know. I just bought a case of r-12 on CL for $80...that's cheaper than r-134 at autozone

06-05-2017, 04:39 PM	#1
tdangle Registered User Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,210	AC Question I'm working on getting my AC up and running. Will be changing over to R134. Since the metal portion of the line from the condenser to the expansion valve is cracked, I removed the line and opened up the back output of the POA valve. I applied 60 PSI of air to the input of the expansion valve and with a gauge hooked up to the low side connector (on the POA) it opens at 27 psi. Should be 29, correct? Am I doing something wrong? Air is going thru the expansion valve then thru the evaporator and then to the POA valve. I think this is the correct setup. __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC

06-05-2017, 05:46 PM	#2
demian5 Registered User Join Date: Aug 2016 Location: Lake Forest, CA Posts: 2,177	Re: AC Question When AC pressures are in the 100s, does 2 psi matter? __________________ "Work hard, use your vacation days." 1970 C15 GMC Long Bed 1986 C20 Scottsdale 1983 K2500 Sierra Classic Suburban 6.2 Instagram: C10sofOC

06-05-2017, 07:26 PM	#4
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: AC Question Good luck with your conversion. If you have factory AC it will NOT work anywhere near as good as with r-12. I'm restoring the factory AC on my truck and will be using r-12. I've done this enough times to know better now As soon as it gets into the 90s here your AC won't work with r-134...ask me how I know. I just bought a case of r-12 on CL for $80...that's cheaper than r-134 at autozone __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man



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