Opel 1900 1973, Service Manual

Page: 599 / 625

AIR CONDITIONER SYSTEM -OPEL 1900 MANTA
91
FAN DOES NOT RUN Correct electrical fault.
FAN RUNS Check air velocity.
NOT OK Clean evaporator inlets.
Clean evaporator core.
Clean evaporator outlets.
OK Check refrigeration (refer to Refrigeration
Diagnosis Guide).
MAINTENANCE AND ADJUSTMENTS
A D J U S T M E N T O F T H E R M O S T A T I C S W I T C H
The system makes use of a thermostatic switch with
a self-supporting air sensing capillary. This capillary
controls the switch by sensing the temperature of the
air leaving the evaporator fins.
Checking
for Proper
Operation
Install the gauge set and set up the vehicle as
described under FUNCTIONAL TESTING SYS-
TEM
Refrigerant Components Section.
2. Movement of the temperature control knob
should result in a definite change in suction pressure
and cycling of the compressor clutch.
3. If compressor continues to operate regardless of
the knob adjustment, it indicates that the switch
points are fused, which will lead to evaporator
freeze- up. The switch should be replaced.
Adjusting Switch
If, after foregoing checks, the switch seems to be
operating correctly, adjust for proper setting if neces-
sary, as
1. Set up car as described in FUNCTIONAL
TESTING SYSTEM in Refrigerant Components
Section.
2. The suction side of the system, read on the low
pressure gauge, should pull down to the pressure
shown in the chart in SPECIFICATIONS in Refrig-
erant Components Section.
3. the face plate retaining screws and
remove face plate assembly noting the position of the
air capillary so that it can be reinstalled in
the location as when removed. See Figure
Figure Location of Air Sensing Capillary
4. Remove the thermostatic switch retaining screws
and remove switch. Remove the non-metal end plate
from the switch to gain access the switch adjusting
screw. Check the screw for stripped or otherwise
damaged threads.
5. If the low side pressure less than the pre-
scribed pressure at the end of each cooling cycle, turn
the adjusting screw a partial turn clockwise. See Fig-
ure
Figure 1 Adjusting Switch
6. If the pressure was more than the prescribed
value, turn the adjusting screw counter-clockwise.
7. Reinstall switch end plate and install switch in
face plate. Install face plate on assembly
assuring that the air sensing has been re-
placed properly.
8. Check system performance. adjustment
is needed, repeat steps 3 thru 7 until the correct
pressure is reached.
Do not attempt to run a performance test with the
face plate and switch removed
the evaporator
assembly inaccurate reading, will result. Always
replace the switch and face plate assemblies before
checking the system performance.