Heating and Air Conditioning: Testing and Inspection

1. Install manifold gauge set.
2. Run engine at 1500 RPM for ten minutes and set controls for Max A/C with high blower speed.

Fig. 5 A/C System Temperatures:

3. Stabilize A/C discharge air temperature to 70-80°F, Fig. 5.

Fig. 6 A/C System Pressures:

4. Record manifold gauge high and low pressures, Fig. 6.
5. To determine clutch cycle time, record clutch on and off time in seconds.

Fig. 7 Clutch Cycling Rates:

6. Record center register output and ambient temperatures, then compare readings, Fig. 7.

Fig. 8 Performance Test Diagnostic Chart (Part 1 Of 2):

Fig. 8 Performance Test Diagnostic Chart (Part 2 Of 2):

7. If readings are not as indicated, refer to Fig. 8.