RAM 1500 Van V8-5.9L VIN Z LDC (2001)
High Pressure Safety Valve HVAC: Description and Operation
The high pressure relief valve is located on the rear surface of the compressor housing. 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 the valve is faulty.
On new compressor assemblies, a mylar disc is applied to the venting port of the valve. The disc is primarily intended to indicate if the valve has vented
refrigerant during operation. A missing or damaged disc does not indicate failure, but is an indicator of abnormal conditions, and should be diagnosed as
to why venting has occurred. If the mylar disc has loosened or come off, apply a drop or two of refrigerant oil into the valve mechanism through the
venting holes. This will prevent salt, dirt, or moisture from affecting the operation of the valve.
The high pressure relief valve is only serviced as part of the compressor assembly, and must not be removed or otherwise disturbed.
