GMC 1976 ZEO 6083 Maintenance Manual page 72

SAMPLING TUBE
CHIMNEY
REACTION PLATE
BURNER HEAD
BURNER TUBE
. VALVE ASSEMBLY
PROPANE GAS
CYLINDER
T-3877
Figure 27-Leak Detector J-6084
2 . Open control valve only until a low hiss of gas
is heard, then light gas at opening in chimney.
3 . Adjust flame until desired volume is obtained .
This is most satisfactory when blue flame is approxi-
mately 3/8" above reactor plate. The reaction plate
will quickly heat to a cherry red.
4. Explore for leaks by moving the end of the
sampling hose around possible leak points in the
system . Do not pinch or kink hose .
NOTE : Since R-12 is heavier than air, it is good
practice to place open end of sampling tube im-
mediately below point being tested, particularly
in cases of small leaks .
WARNING : DO NOT BREATHE THE FUMES
THAT ARE PRODUCED BY THE BURNING OF
R-12 GAS IN THE DETECTOR FLAME, SINCE
SUCH FUMES CAN BE TOXIC IN LARGE CON-
CENTRATIONS .
5. Watch for color changes. The color of the
flame which passes through the reaction plate will
change to green or yellow-green when sampling hose
draws in very small leaks of R-12 . Large leaks will
be indicated by a change in color to a brilliant blue
or purple ; when the sampling hose passes the leaks,
the flame will clear to an almost colorless pale-blue
again. Observations are best made in a semidarkened
area . If the flame remains yellow when unit is
removed from leak, insufficient air is being drawn in
or the reaction plate is dirty.
AIR CONDITIONING SYSTEM 1- 55
NOTE :
A refrigerant leak in the high pressure
side of the system may be more easily detected
if the system is operated for a few minutes, then
shut off and checked immediately (before system
pressures equalize). A leak on the low pressure
side maybe more easily detected after the engine
has been shut off for several minutes (system
pressures equalized) ; this applies particularly to
the front seal .
AVAILABILITY OF
REFRIGERANT-12
Refrigerant-12 is available in 30 lb . and in 15 oz .
disposable containers .
Normally, air conditioning systems are charged
making use of the Charging Station which uses the
30 lb . container. Evacuating and charging proce-
dures are noted later in this section.
The 15 oz . disposable cans are generally used for
miscellaneous operations such as flushing .
WARNING : THE FOLLOWING PRECAUTIONS
SHOULD BE OBSERVED WHEN ADDING RE-
FRIGERANT TO A SYSTEM USING 15 OZ . DIS-
POSABLE CANS :
1 . Do not charge while compressor system is hot.
2. Empty container completely before disposing.
3 . Use opening valves designed for use with con-
tainer - follow valve manufacturer's directions care-
fully.
4. Always use pressure gauges before and during
charging.
5 . NEVER connect on high pressure side of sys-
tem or to any system having a pressure higher than
indicated on refrigerant containers .
6. If inexperienced, seek professional assistance .
COMPRESSOR OIL
Special refrigeration lubricant should be used in
the system . This oil is as free from moisture and
contaminants as it is possible to attain by human
processes. This condition should be preserved by im-
mediately capping the bottle when not in use .
See "Air Condtiioning System Capacities" for
the total system oil capacity .