Refrigerant System

Refrigerant System Performance Test

Conduct a complete refrigerant loop performance test. During the procedure, be sure to:

^ Disconnect the ambient sensor and short the wiring connector. This will set the air mix door to the FULL COLD position. Visually confirm that the air mix door is in the full cold position.

^ Set engine idle to 1500 rpm.

^ Operate the system for 10 minutes MINIMUM before recording data.

^ Record refrigerant high pressure and low pressure readings and discharge air temperature

Out of specification pressure readings

Low side pressure is too high, check the following:

1. Condenser/electrical cooling fan operation.

2. Engine driven cooling fan coupling operation.

If these cooling fans are operating normally, but the refrigerant system low side pressure is above specification, the system may be overcharged. Recover the refrigerant, evacuate the system and recharge with the correct amount of refrigerant.

Low side pressure is too low (but not in a vacuum) and the refrigerant high side pressure reading is also low the system may be undercharged. Recover the refrigerant, evacuate the system and recharge with the correct amount of refrigerant.

Refrigerant System Inspection

The Refrigerant System has five (5) major components:

1. Compressor

2. Evaporator

3. Thermal Expansion Valve

4. Liquid Tank

5. Condenser

The operation of these components can be evaluated by touching the inlet and outlet of each component to determine the temperature.

Prior to performing the temperature touch evaluation, ensure that the compressor clutch is engaged and is not cycling on and off. If the compressor clutch is not engaged or is cycling on and off, check for system pressures that may be too low or excessive. If pressures are OK, check the dual pressure switch on the liquid tank and the compressor wiring harness.