Performance Test

Fig. 6 Placement of Dry & Wet-Dry Thermometers For A/C Functional Test.:

1. Connect manifold and gauge set to A/C compressor.
2. Open all windows and doors. Turn A/C on with blower switch on Hi and temperature lever on Cold.
3. Start engine and keep compressor speed at 2000 RPM.
4. Place wet and dry bulb thermometer near inlet of cooling unit and dry bulb thermometer in cool air outlet, Fig. 6.
5. Check reading on high pressure gauge. Reading should be within 200 to 220 psi. If reading is above 220 psi, pour water over condenser. If reading is below 200 psi, cover front of condenser. Dry bulb thermometer at air inlet should read between 77 to 95 deg. F. After these conditions are achieved, run A/C until high and low gauges and thermometers stabilize.

Relative humidity graph:

6. Read wet and dry bulb thermometer at air inlet and determine relative humidity from chart in Fig. 7.
7. Read temperature at air outlet and air inlet and determine difference between the two.

Fig. 8 A/C Functional Test Chart.:

8. Using relative humidity and difference between air inlet and air outlet temperatures, determine if system is working satisfactorily by using chart in Fig. 8. Example given shows a relative humidity (step 6) of 60% and a difference in temperature of 17 deg. C. The points intersect within lines on graph, so system is satisfactory.