Opel 1900 1973 Service Manual page 599

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
ADJUSTMENT OF THERMOSTATIC SWITCH
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 Operation
for Proper
described under FUNCTIONAL TESTING SYS-
TEM iti 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 ihe foregoing checks, the switch seems to be
operating correctly, adjust for proper setting if neces-
sary, as ~follows:
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. Remove the face plate retaining screws and
remove face plate assembly noting the position of the
air sensipg capillary so that it can be reinstalled in
the same location as when removed. See Figure 98.
AIR CONDITIONER SYSTEM -OPEL 1900 - MANTA
Figure 98.170
4. Remove the thermostatic switch retaining screws
and remove switch. Remove the non-metal end plate
from the switch to gain access tq the switch adjusting
screw. Check the screw for stripped or otherwise
damaged threads.
5. If the low side pressure was less than the pre-
scribed pressure at the end of each cooling cycle, turn
the adjusting screw a partial turn clockwise. See Fig-
ure 9B-171.
Figure 9B-17
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 ,evaporator assembly
assuring that the air sensing c&pillary has been re-
placed properly.
8. Check system performance. Fffurther 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 ,from the evaporator
assembly - inaccurate reading, will result. Always
replace the switch and face plate assemblies before
checking the system performance.
Location of Air Sensing Capillary
1 Adjusting Thkmosfatic Switch