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Trying to understand pressure readings

MoleQLR Dano on Tue July 01, 2014 11:04 PM User is offline

Year: 2000
Make: GMC
Model: Sierra 1500 2WD
Engine Size: 5.3L
Refrigerant Type: R134a
Ambient Temp: 86F
Pressure Low: 100
Pressure High: 120
Country of Origin: United States

Compressor is short cycling staying on no longer than about 4 seconds. Static pressure is 105 with the engine off. Start the engine and engage the AC system and the compressor comes on and draws the Low Side down to 25psi and the High Side goes up to 120, then the compressor disengages and the Low Side comes up to 90 psi and the High Side drops to 100psi. Compressor then re-engages and starts the cycle again. I have not added any refrigerant to the system.

Any thoughts?

I'm wondering if the accumulator has gone bad and I have a partially clogged or clogged orifice tube, but I'm not sure the pressures accurately reflect that. From what I understand the High Side pressures with the compressor engaged would be much larger if that was the case.

I live in south central Florida and I travel the state a lot for work so it's getting a little rough out there when there are no storm clouds for shade and cool rain.



TRB on Tue July 01, 2014 11:15 PM User is offlineView users profile

In a case like this you really need to know if you have a properly charged system. I suggest reclaiming the refrigerant, pulling a vacuum and recharging back to spec.


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