04
Air
Conditioning
System
Manual
------
Rofls-Royce
&
Bentley
----
-----
-
--
-
few seconds
and
then re-tighten.
Hook
a
spring
balance to the
container
and
record the weight.
Open
the vacuum valve
of
the manifold
gauge
set
and
allow approximately
one
pound
of
gas to pass
into the evacuated system. In some cases
one
pound
of
gas will not flow into the system, so allow the
amount
to pass into the system which will balance
the system pressure with the Freon
12
container
pressure. Allow the
dry
Freon introduced into the
system to remain for a period
of
IO
minutes.
Do
not
allow the pressure reading
on
the
compound
gauge
to exceed
50
lb/sq. in. This can be
controlled
by
regulating the manifold gauge set vacuum valve.
Switch
off
the system
and
switch
off
the ignition.
Purge the
Freon
in the system by
introducing
an
additional
Freon
charge as follows:
Remove the manifold gauge set from the compres-
sor
service valves, set the service valves to their
midway position to allow the Freon remaining in the
system
to
escape to atmosphere.
Connect
the hose
of
the high pressure gauge to the discharge service
port
of
the compressor. With the manifold
gauge
set
connected
to the
Freon
container,
the
compound
gauge valve closed
and
the high pressure gauge valve
open,
allow
Freon
from the container to pass into the
discharge service port,
through
the service
port,
through
the condenser, filter drier,
evaporator
and
out
through
the service
port
of
the suction (service)
valve. Allow this
operation
to
continue
for
approxi-
mately
five
seconds.
CHARGING
It
is
necessary to
draw
out
the remainder
of
the
refrigerant
put
in
during
the sweeping
operation
before charging fully. Repeat the evacuation process
and
switch off.
Back-seat the high pressure service valve
and
forward-seat the low pressure service valve. Re-
connect
the centre union
of
the manifold
gauge
set
with
the refrigerant container,
and
open
the valve
on
the
container. Break the manifold
centre
hose
joint
and
purge
the
air
for a few seconds,
then
re-tighten.
Hook
a
spring
balance
to
the refrigerant
container
Sec1inn
C6
and
record the weight.
Open
the vacuum valve
of
the
manifold gauge set.
Start
the engine
and
switch
on
the blowers.
If
the
refrigerant will
not
flow into the system even with the
compressor
in
operation
stand
the
container
in a
bucket
of
warm
water
not
exceeding 113°F.
Do
not
apply
a flame,
or
localised heat.
This
could
cause
an
explosion.
Do
not
allow the reading
on
the
com-
pound
gauge
to
exceed 50 lb/sq. in. This
can
be
controlled by regulating the manifold gauge
set
vacuum valve.
When
31-4 lbs. refrigerant has been
drawn
into
the
system, switch
off
and
close the manifold gauge
set
vacuum valve.
Close the valve
of
the
Freon
12
container
and
disconnect the centre hose. Back-seat
both
service
valves
on
the compressor. Disconnect
and
remove
the manifold gauge set
and
replace protective covers
on
service valves.
Check
the system for leaks, using
a detector lamp.
LEAK DETECTION
Leak detection
should
be carried
out
at
full
operat-
ing pressure (see
under
pressure tests for
appropriate
figures)
and
under
static
conditions
by means
of
the
Detector Lamp. In
order
to
obtain
the
correct
pressure, it
may
be necessary to re-charge the system.
Light the detector lamp
and
move the open end
of
the flexible hose
round
all points where leaks
are
possible.
The
colour
of
the
lamp
flame will change
to
green when the open
end
passes
over
a leak point.
It
is
important
not
to
operate
the
lamp
pressure
pump
while
in
the vicinity
of
possible leaks because
refrigerant will be
drawn
into
the body
of
the lamp
and
the flame will thus remain green for some time,
and
be unusable
as
a leak detector.
Furthermore, the
car
should
be placed in a position
where there is
adequate
ventilation, otherwise refri-
gerant
may
persist in the vicinity
of
the
car
and
give
misleading results; however,
draughts
should
not
be
prevalent
or
the seepage
of
gas in a
particular
area
of
a possible leak
could
dissipate
without
detection.
(An
alcohol
leak
detector
may
be used similarly
as
above).
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