Originally posted by RoadRunner:
Originally posted by eric1:
Condenser is High side pressure. Relief on r-134a is usually 380 PSI.
Working pressures on the car are in the 150 to 200 PSI range with excursions into 300 psi not unusual.



Okay,

Here is an overview of your AC system in case you wondered how it all worked...

Compressor -> Accumulator(Dryer) -> Evaporator -> Orifice -> Condensor -> Compressor.

Everything between the Compressor and the Orifice is HIGH PRESSURE.
Everything between the Orifice and the Compressor is LOW Pressure.
The Orifice is a very small tube, surrounded by a very fine filter.
This is the only part responsible for the HIGH/LOW side pressures,
and can cause a lot of problems if it is clogged with metal shavings
from a worn out and poorly lubricated compressor.





Compressor -> Condenser -> Accumulator -> orifice (Or expansion Valve) -> Evaporator -> Compressor

Compressor - Low pressure Cold gas compressed to High pressure hot gas
Condenser - Hot gas "condensed" to high pressure liquid
Accumulator - Gives room for expansion, contraction, sort of a reservoir - can also filter and dry. Some systems have separate accumulators and filter/driers.
Orifice : High Pressure liquid to low pressure liquid
Evaporator : low pressure liquid, boiled by heat in air, becomes low pressure gas
Back to compressor to start cycle over.

FWIW, I think road-runner knew this (IMHO) and just typed it in the wrong sequence. The rest of his statements are absolutely corrrect.

AS RR said, every thing from the compressor to the orifice is high pressure when running. When the system is off, the pressure equalizes in the system and will be at a pressure that corrresponds to the saturated pressure of 134a for the ambient temperature.

My name is Richard. I was a Contouraholic. NOW: '02 Mazda B3000 Dual Sport, Black BEFORE: '99 Contour SE Sport Duratec ATX Spruce Green PIAA 510's, Foglight MOD, K&N Drop-in