AC R134a conversion && line pressure
Thread Starter
Safety Car
Joined: May 1999
Posts: 4,693
Likes: 10
From: Carefree, Arizona
2017 C7 of Year Finalist
AC R134a conversion && line pressure
After my old AC compressor went to heaven in my '89 I installed a new one and converted to R134a with one of those kits, I even bought a pressure gage to double check (next is my '82 :) ).
Everything went well, cooling is good exept that the compressor seem to run all the time. Low line pressure is between around 25 PSI, high line pressure is a little over 200 PSI.
Does anyone know at what pressure the pressure switch is supposed to disengage the compressor clutch? :confused:
Since the clutch from the last compressor starting smoking while driving through the deset, I don't want to risk trashing another compressor with a non functional switch. :cry
Any help apreciated....
Andy
[Modified by andy82, 8:50 PM 4/18/2002]
Everything went well, cooling is good exept that the compressor seem to run all the time. Low line pressure is between around 25 PSI, high line pressure is a little over 200 PSI.
Does anyone know at what pressure the pressure switch is supposed to disengage the compressor clutch? :confused:
Since the clutch from the last compressor starting smoking while driving through the deset, I don't want to risk trashing another compressor with a non functional switch. :cry
Any help apreciated....
Andy
[Modified by andy82, 8:50 PM 4/18/2002]
Melting Slicks
Joined: Apr 2001
Posts: 2,121
Likes: 223
From: Ca.
Re: AC R134a conversion && line pressure (andy82)
It's adjustable-the screw thats under the wire plug on the low press. switch-but I'd rather have it engaged to cool better at idle, I turned mine down so it will engage and stay engaged at about 20lbs low side press.
Drifting
Joined: Dec 2000
Posts: 1,733
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From: Sarasota FL
Re: AC R134a conversion && line pressure (andy82)
The correct setting is about 25 to 28 psi. This corresponds to the freezing temperature for R134a, in the evaporator. Any lower and ice may form at low loads.
Run the engine at about 2000 rpm to simulate cruising speed and the compressor shoud bring the pressure slowly down to the cut off and re-engage as the pressure rises. It may not cycle off at all if the car is very hot inside or you may have to run the engine a little faster.
Compressor operation is optimized for about 1500 to 2000 rpm. At idle the efficency is way down and the compressor shouldn't cycle unless the charge is low.
Run the engine at about 2000 rpm to simulate cruising speed and the compressor shoud bring the pressure slowly down to the cut off and re-engage as the pressure rises. It may not cycle off at all if the car is very hot inside or you may have to run the engine a little faster.
Compressor operation is optimized for about 1500 to 2000 rpm. At idle the efficency is way down and the compressor shouldn't cycle unless the charge is low.
Thread Starter
Safety Car
Joined: May 1999
Posts: 4,693
Likes: 10
From: Carefree, Arizona
2017 C7 of Year Finalist
Re: AC R134a conversion && line pressure
Thanks for the help guys. Much appreciated!
If I understand correct the compressor engages if the pressure is above a certain PSi level on the low pressure side??
Andy
If I understand correct the compressor engages if the pressure is above a certain PSi level on the low pressure side??
Andy
Drifting
Joined: Dec 2000
Posts: 1,733
Likes: 0
From: Sarasota FL
Re: AC R134a conversion && line pressure (andy82)
Thanks for the help guys. Much appreciated!
If I understand correct the compressor engages if the pressure is above a certain PSi level on the low pressure side??
Andy
If I understand correct the compressor engages if the pressure is above a certain PSi level on the low pressure side??
Andy
