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HVAC
A/C SYSTEMPERFORMANCE TEST
1. Place the vehicle in a ventilated, shaded area free
from excessive draught, with the doors and
windows open.
2. Check that the surface of the condenser is not
restricted with dirt, leaves, flies, etc. Clean as
necessary.
3. Switch on the ignition and the air conditioner air
flow control. Check that the blower is operating
efficiently at low, medium and high speeds.
4. Switch off the blower and the ignition.
5. Check that the evaporator condensate drain tubes
are open and clear.
6. Check the tension of the compressor driving belt,
and adjust if necessary.
7. Inspect all connections for the presence of
refrigerant oil. If oil is evident, check for leaks, and
repair as necessary.
NOTE:
The compressor oil is soluble in refrigerant R134a
and is deposited when the refrigerant evaporates
from a leak.
8. Start the engine.
9. Set the temperature controls to max. cold and
switch the air conditioner blower control on and off
several times, checking that the magnetic clutch
on the compressor engages and releases each
time.
10.With the temperature control at maximum cooling
and the blower control at high speed, warm up the
engine and fast idle at rated rpm.
11. Gradually increase the engine speed to the high
range and check the sight glass at intervals.
12.Check for frosting on the service valves.
13.Check the high pressure hoses and connections
by hand for varying temperature. Low temperature
indicates a restriction or blockage at that point.
14.Switch off the air conditioning blower and stop the
engine.
15.Ifthe air conditioning equipment is still not
satisfactory, carry out a pressure test as previously
described in this section.
LEAK TEST SYSTEM
The following instructions refer to an electronic type
Refrigerant Leak Detector for use with R134a, which
is the safest and most sensitive.
1. Place the vehicle in a well ventilated area but free
from draughts, as leakage from the system could
be dissipated without detection.
2. Follow the instructions issued by the manufacturer
of the particular leak detector being used.
3. Commence searching for leaks by passing the
detector probe around all joints and components,
refrigerant gas is heavier than air.
4. Insert the probe into an air outlet of the evaporator
or into the evaporator drain tube.
Switch the air conditioning blower on and off at
intervals of ten seconds. Any leaking refrigerant
will be gathered in by the blower and detected.
5. Insert the probe between the magnetic clutch and
compressor to check the shaft seal for leaks.
6. Check all service valve connections.
7. Check the condenser for leaks at the pipe unions.
8. If any leaks are found, the system must be
discharged before rectification.
9. Rectify any leaks and recheck for leaks during
evacuation prior to charging.