Checking For Leaks; Use Of Sight Glass - Ford COUGAR 1968 Shop Manual

PART 16-2
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Air Conditioning
16-27
I F NOT OK
Correct the cause of the obstruction
or bind condition (if required). Lubri-
cate door edges and plenum chamber
contact surfaces with Lubriplate. Lubri-
cate door pivot points. If door was
not obstructed or binding, replace the
applicable door motor. Check the
doors and control system for proper
operation.
T EST ING
Obstructed air passages, broken
belts, disconnected or broken wires,
loose clutch, loose or broken mount-
ing brackets may be determined by
visual inspection of the parts.
CHECKING FOR LEAKS
Attach the manifold gauge set (Fig.
12). Leave both manifold gauge valves
a t the maximum clockwise position.
Set both service valves a t the center
position. Both gauges should nbw
show spproximately 60 to 80 pounds
pressure a t 75 degrees F. If very little
or no pressure is indicated, leave the
vacuum pump valve closed, open the
Refrigerant-12 tank valve, and set the
low pressure manifold gauge valve to
the counterclockwise position. This
opens the system to tank pressure.
Check all connections, and the com-
pressor shaft seal for leaks, using a
flame-type leak detector (Fig. 13). Fol-
low the directions with the leak detec-
tor. The smaller the flame the more
sensitive it is to leaks. Therefore, to
insure accurate leak indication keep
the flame as small as possible. The
copper element must be red hot. If it
is burned away, replace the element.
Hold the open end of the hose at each
suspected leak point for two or three
seconds. The flame will normally be
almost colorless. The slightest leak
will be indicated by a bright green blue
color to the flame. Be sure to check
the manifold gauge set and hoses for
leaks as well as the rest of the system.
If the surrounding air is contam-
inated with refrigerant gas, the leak
detector will indicate this gas all the
time. Good ventilation is necessary
to prevent this situation. A fan, even
in a well ventilated area, is very help-
ful in removing small traces of refrig-
erant vapor.
USE O F S I G H T GLASS
Clean the sight glass before check-
ing for a proper charge of refrigerant.
Then, observe the sight glass for
LOW PRESSURE GAUCE
HlGH PRESSURE GAUGE
FIG.
12-Manifold Gauge Set
bubbles with the engine running a t
1500 rpm and the A / C controls set a t
maximum cooling. Bubbles in the
sight glass indicate an undercharge of
refrigerant. If an undercharge of re-
frigerant is found, check the system
for leaks. Repair any leaks, evacuate
the system, and charge the system with
the proper amount of Refrigerant-12.
N o bubbles in the sight glass indi-
cate either a full charge of refrigerant
or a complete loss of refrigerant.
While observing the sight glass, cycle
the magnetic clutch off and on, with
the engine running at 1500 rpm. Dur-
ing the time the clutch is off, bubbles
will appear if refrigerant is in the sys-
tem and will disappear when the
clutch is on. If no bubbles appear dur-
ing the on and off cycle of the magnet-
ic clutch, there is no refrigerant in the
system. If there is no refrigerant in
the system, it will be necessary to
leak test, repair as required, and
charge the system. Under conditions
of extremely high temperatures, oc-
casional foam or bubbles may appear
in the sight glass.
CHECKING SYSTEM
P R E S S U R E S
The pressures developed on the
high pressure and low pressure side of
the compressor indicate whether or
not the system is operating properly.
Attach the manifold gauge set
(Fig. 12). It will not be necessary to
attach the Refrigerant-12 tank un-
TO HlGH PRESSURE
SERVICE VALVE
K 1 W - 0
FIG.
13-Torch Type Leak Detector
less refrigerant is to be $died to the
system. Set both manifold gauge
valves at the maximum clockwise, or
closed, position. Set both service valves
a t the center position.
3
+?
; : : $ a
Check the system pressures with
the engine running at lS!Mrtpm, all
controls set for maximum cooling, and
the front of the car at least 5 feet from
any wall.
The actuai pressures indicated on
the gauges will depend on the tem-
perature of the surrounding air and
the humid~ty. H ~ g h e r air temperatures
along with high humidity, will give