Page 1122 - Workshop Manual - Aumark (BJ1051)

51-30
Heater and AC-Refrigerant oil

Refrigerant

Inspection on vehicle

It is better to have suitable pressure inside of AC system for leak detection and the pressure should
reach to at least 0.34MPa. But it is not allowed to charge compressed air into AC system; otherwise
the moisture, dust and other impurities in the air will increase the burden of dryer or contaminate
system. There are following methods to check if the refrigerant air is leaking:
Notes:
Partial refrigerant will stay inside of refrigerant oil of compressor if AC system is evacuated when
there is refrigerant left in the system. This kind of left refrigerant will evaporate continuously which
will cause the reading of pressure meter increases a little during leak detection (at most 2 scale
divisions); but the increased pressure does not mean there is leaking in the AC system.
1. Measure refrigerant pressure by manifold pressure meter
(a). This method is used to find out where the malfunction is by manifold pressure meter. Read
the numerical value of manifold pressure meter when the following conditions are met.
Test conditions:
Air intake temperature is 30 ~ 35 ℃
Engine speed is 1500rpm
Blower speed is on HI shift
Thermostat switch is on COOL shift
AC switch is on ON
Door is opened completely

z Normal working conditions of
refrigerating system.
51 Readings of pressure meter:
Low pressure side: 0.15 ~ 0.25 MPa
High pressure side: 1.37 ~ 2.37 MPa

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