A/C System Refrigerant Flow

A/C System Refrigerant Flow:

The compressor is driven by a drive belt from the engine crankshaft through the compressor clutch pulley. The compressor pulley rotates freely, without turning the compressor shaft, until an electromagnetic clutch coil is energized. When voltage is applied to energize the clutch coil, a clutch plate and hub assembly is drawn rearward toward the pulley. The magnetic field locks the clutch plate and pulley together as one unit to drive the compressor shaft.

As the compressor shaft turns, the compressor performs two main functions: It compresses the low-pressure refrigerant vapor from the evaporator into a high-pressure, high-temperature vapor. The compressor pumps refrigerant and refrigerant oil throughout the air conditioning system.

PRESSURE RELIEF VALVE
The compressor is equipped with a pressure relief valve which is placed in the system as a safety factor. Under certain conditions, the refrigerant on the discharge side may exceed the designed operating pressure. To prevent system damage, the valve is designed to open automatically when the high side pressure exceeds a specified amount. Conditions that might cause this valve to open (defective A/C pressure sensor, inoperative cooling fan, etc.) should be corrected, and the refrigerant oil and refrigerant should be replaced as necessary.