Grand Voyager V6-3.0L VIN 3 (1998)
High Pressure Safety Valve HVAC: Description and Operation
SYSTEM OPERATION
A/C Pressure Transducer
A/C Pressure Transducer
The A/C Pressure Transducer monitors the refrigerant gas pressure on the high side of the system. The transducer is located on the liquid line. The
pressure transducer turns off the voltage to the compressor clutch coil when refrigerant gas pressure drops to levels that could damage the
compressor. The transducer also is used to adjust condenser fan speeds and will turn off compressor at high refrigerant pressures. The pressure
transducer is a sealed factory calibrated unit. It must be replaced if defective. 0-ring replacement is required whenever the pressure transducer is
serviced. Be sure to use the 0-ring specified for the transducer.
Compressor High-Pressure Relief Valve
The High Pressure Relief Valve prevents damage to the air conditioning system if excessive pressure develops. Excessive pressure can be caused
by condenser air flow blockage, refrigerant overcharge, or air and moisture in the system.
The high pressure relief valve vents only a small amount of refrigerant necessary to reduce system pressure and then reseats itself. The majority of
the refrigerant is conserved in the system. The valve is calibrated to vent at a pressure of 3450 to 4140 kPa (500 to 600 psi). If a valve has vented
a small amount of refrigerant, it does not necessarily mean the valve is defective.
The High Pressure Relief Valve is located on the compressor manifold at the discharge passage.
NOTE: Special effort must be used to keep all R-134a system components moisture free. Moisture in the oil is very difficult to remove and will cause
a reliability problem with the compressor.
