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AIRCONDITIONING
b. Manifold Gauge (Refrigeration Cycle)
This is a method where trouble is detected and
repaired by using manifold gauge. The manifold
gauge indicates the refrigeration cycle high and
low pressure side pressures on the respective
gauge.
Important
Be sure to purge out the air in the charging
hoses of the manifold gauge by using the
refrigerant pressure in the cycle.
1. When Normal:
Conditions
* After the engine has warmed - up, check the
following conditions (for HFC 134a).
Engine Speed: 1500rpm
A/C inlet temperature: 30' -35' C (86' - 95' F)
Blower Speed: Hl
Temperature control: Maximum cooling.
Reference
Gauge indications before A/c operation
Both high and low pressure sides:
5-8 kg/cm’ (0.5 - 0.8 MPa)
Caution
*Precautions for ERR system Since the low
pressure side pressure (within the evaporator)
is controlled with the ERR, even when there is
an abnormality, an abnormal value does not
always appear directly in the pressure gauge.
Pay particular attention to this when trouble-
shooting.
2. Insufficient Refrigerant
Problem
Cause
Check and
remedy
1. Pressure is low on Quantity of,
-Check for gas
both the low refrigerant is leakage and repair
pressure and the too small-
-Replenishment of
high pressure
refrigerant
sides
If indicated pressure
2 Bubbles can be Gas leakage is near 0 when
seen in the light
connected to gauge,
glass.
evacuate the air
3. Air being blown
after checking and
out is not cool.
locating of the leak.
Fig. 53 - Normal condition
Fig. 54 - Insufficient refrigerant