HARRIER SERVICE MANUAL PART -1

FATC 49 e) PRESSURE TEST USING MANIFOLD GAUGES This is a method where trouble is detected and re- paired by using manifold gauge. The manifold gauge indicates the refrigeration cycle high and low pres- sure side pressures on the respective gauge. NOTE Make sure following conditions are fulfilled before getting the correct gauge readings (after engine has warmed –up ) Engine speed 1500rpm A/C inlet temperature (Ambient Temperature) 30° - 35° C (86° - 95° F) Blower speed High Temperature Control Full cold Reference value be- fore AC operation at both high and low pressure sides 5-8 kg/ cm 2 (0.5 - 0.8 MPa) Based on the values the following conclusions can be inferred and further troubleshooting can be done. Low Pressure side in kg/cm 2 ( M Pa) High Pressure side in kg/cm 2 ( M Pa) Remarks Symptoms Possible rea- sons 1.5-2.5 (0.15-0.25) 14-16 (1.37-1.57) System pressure is normal Normal cooling AC system work- ing normal 0.5-1.0 (0.05-0.1) 7-10 (0.69-0.98) Pressure low Insufficient cool- ing 1. Refrigerant quantity too small. 2. Gas leakage. Vacuum 5-6 (0.5-0.6) Refrigerant fails to circulate No cooling expe- rienced Clogging of AC cycle. Initially 1.5-2.5 (0.15 -0.25) and later vacuum Initially 14-16 ( 1.37- 1.57)and later 7-10 (0.69-0.98) Moisture present in system. Initially works normally but later no cooing experi- enced Freezing of ex- pansion valve due to presence of moisture. 4-6 (0.4-0.6) 7-10 (0.69-0.98) Pressure on low pressure side is high and pressure on high pressure side is low. No cooling. Compressor De- fective.