Component Tests

Refrigerant Pressure & Temperature Charts:

Refrigerant System Pressure Evaluation Chart:

R-134a systems require the use of special service equipment designed specifically for R-134a systems. R-12 servicing equipment cannot be used on R-134a systems.
Refrigerant system problems are diagnosed by checking refrigerant pressures and clutch cycle rate and times. Compare pressures and cycle time to charts shown in Fig. 1 and 2. Conditional requirements for refrigerant system tests must be satisfied to obtain accurate pressure readings. If findings do not fall between lines on respective charts, refer to Fig. 3, to determine specific cause of improper readings.
After necessary repairs have been performed, take pressure readings while meeting conditional requirements to ensure problem has been corrected.
Visual inspection of the system may determine problems with the refrigerant system. By making a visual inspection, some of the following problems can be diagnosed: obstructed air passages, broken belts, disconnected or broken wires, loose or broken mounting brackets and refrigerant leaks.
A refrigerant leak will usually appear as an oily residue at the leakage point in the system.