Air
Conditioning
System
Manual
-------
Rolls-Royce
&
Bentley-------------
Fig.
l 7 Manifold
gauge
set
in
poaition
Open
the valve
of
the
Freon
12
container, purge
the
air for a few seconds
and
then re-tighten.
Attach
a spring balance
to
the
container
and
record
the
weight.
Open
the
vacuum
valve
of
the manifold gauge
set
and
allow I lb.
of
gas
to
pass
into
the system.
In
some
cases,
when
the
temperature
(and
there-
fore
the
pressure)
is low,
it
may
be
necessary
to
start
the engine
and
switch
on
the system in order
to
draw
in
the
refrigerant. Owing to the variation
in
the
time
taken
to
charge
,
the
weight
of
refrigerant
remaining
in
the
container
must
be
checked
frequently.
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
compressor
and
the ignition.
Close
the
manifold
gauge
set
vacuum
valve
and
back-seat
the
compressor
low pressure service
valve by turning it anti-clockwise. Close the valve
of
the
refrigerant
container
and
disconnect
the
centre
hose.
Start
the
engine
and
operate
the
Page 28
system
for
approximately
10
minutes
with
the
blower
motors
at
full
speed
.
Switch
off
the
system
and
switch
off
the
ignition.
If
the
system
fails
to
hold
the
vacuum
when
testing,
it
is
necessary
at
this
stage
to
locate
~he
leak; this is possible
because
the system is under
pressure
and
escape
of
refrigerant
can
be detected
(see
Section
on
Leak
Detection).
If
the
system
maintains
the
vacuum
it
is
ready
for charging
upon
completion
of
the
sweeping
operation.
Ensure
that
the
valves
on
the
manifold
gauge
set
are
closed.
Turn
the high pressure service
valve two complete
turns
clockwise.
Drain
the
system
by slightly
opening
the
pressure valve
of
the
manifold gauge set.
TO
CHARGE
Before charging, it is necessary
to
draw
out
the
refrigerant remaining from the s\Veeping operation.
Repeat
the evacuation process (see Page 27).
To Next Page
Loading...
