RAM 2500 Truck 2WD V8-5.7L VIN D (2004)
High Pressure Safety Valve HVAC: Description and Operation
A high pressure relief valve is located on the compressor cylinder head, which is on the rear of the compressor. This mechanical valve is designed to vent
refrigerant from the system to protect against damage to the compressor and other system components, caused by condenser air flow restriction or an
overcharge of refrigerant.
The high pressure relief valve vents the system when a discharge pressure of 3445 to 4135 kPa (500 to 600 psi) or above is reached. The valve closes
when a minimum discharge pressure of 2756 kPa (400 psi) is reached.
The high pressure relief valve vents only enough refrigerant to reduce the system pressure, and then re-seats itself. The majority of the refrigerant is
conserved in the system. If the valve vents refrigerant, it does not mean that the valve is faulty.
The high pressure relief valve is a factory-calibrated unit. The valve cannot be adjusted or repaired, and must not be removed or otherwise disturbed. The
valve is only serviced as a part of the compressor assembly.
