Air
Conditioning
System
Manual
-------
Rolls-Royce &
Bentley------------
Air
delivery
Switch
on
the blower motors
and
check the
air
delivery
at
the duct outlets. This should
be
carried
out
over the full range
of
switch positions.
Failure
of
one system in all switch positions
indicates a blocked intake
or
filter, a defective
blower motor
or
flap actuator, or faulty wiring.
Failure
of
the fresh air blower
motor
to operate
when the knob
of
the upper airstream switch is in
the pushed-in (medium speed) position only,
indicates a defective resistance
or
switch
or
a
wiring fault. Failure
of
the recirculation blower
motor
to
operate
in the medium speed positions
(1st
and
2nd clockwise
and
1st anti-clockwise)
of
the lower airstream switch will probahly be due to
a similar defect.
A failure in
one
switch position will probably
be
caused by defective switch contacts. Complete
failure indicates a fuse, switch
or
wiring defect.
Refrigerant
circulation
Initial
procedure
Site the
car
in a well ventilated and shady
position. Check the tension
of
the compressor
driving belts
and
the external cleanliness
of
the condenser, as detailed in the Maintenance
Schedule.
Start
the engine
and
allow it to
run
at
a fast idle,
operating the refrigeration system with the blower
motors
at
full speed. Visually check
that
the
magnetic clutch is operating.
Fault
location
An obstructed condenser matrix
cannot
function
efficiently
and
will result in insufficient cooling and
high
compressor
head pressures.
Blowers
and
compressor
opera.ting
-
No
cooling
Possible causes are as
follows:-
1.
Low
refrigerant charge.
2.
An inoperative thermostat
or
solenoid valve.
3.
A restriction in the refrigerant circuit.
4.
Incorrect functioning
of
the
compressor
valves.
Page
2.4
5.
A faulty expansion valve.
6. Blower
motor
incorrectly installed.
The following action should
be
taken:-
1.
Check the system for leaks
and
rectify, then
re-charge.
2.
Test the operation
of
the thermostat and
solenoid valves
and
adjust
or
renew a
faulty thermostat; service
or
renew a defec-
tive solenoid valve.
3.
Inspect
all hoses
and
pipes for
kinks
and
check
that
the
expansion
valves are
operating.
4. Test compressor head pressures
and
valves
(see Page
15).
5.
Test the expansion valves for correct
operation;
if
faulty, remove
and
clean
or
if
necessary renew the unit.
6. Check
that
the blower
motor
and
impeller
housing
have
not
been
installed
facing
in
the reverse direction. This will cause a
flow
out
of
the intake. Reversing the motor leads
will
not
effect a cure.
Blowers
operating
-
Partial
cooling
Possible causes:
1.
Low refrigerant charge.
2.
A defective expansion valve.
3.
The
compressor operating above normal
pressure.
4. Restricted condenser tubes
or
discharge
line.
5.
A faulty thermostat
or
solenoid valve.
6.
The
condenser
matrix
obstructed.
7.
Incorrect refrigerant.
Action to
be
taken:
1.
Check
the system for leaks
and
re-charge.
2.
Test
the
expansion
valve, clean,
adjust
or
ren:ew.
3.
Test the compressor head pressures (see
Page
15)
and
if
necessary inspect the valves.
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