Chevrolet 30 Series 1967 Service Manual page 44

HEATER AND AIR CONDITIONING 1A-16
FIVE A M P
TIME D ELAY
FUSE
C O R D TO
110 A C S O U R C E
Fig . 26 - Vacuum Pump
CAUTION: Do not breathe the fumes that are
produced by the burning of R-12 gas in the de-
tector flame, since such fumes can be toxic in
large concentrations of R-12.
4. Watch for color changes. The color of the flame
which passes through the reaction plate will change
to yellow when sampling hose draws in very small
leaks of R-12. Large leaks will be indicated by a
change in color to a vivid purplish-blue. When the
sampling hose passes the leak, the flame will clear
to an almost colorless pale-blue again. If the flame
remains yellow when unit is removed from leak,
insufficient air is being drawn in or the reaction
plate is dirty.
P U M P PU M P D IS C H A R G E
INLET OUTLET
Fig . 27 - Refrigerant-12 Disposable Cans and V alves
NOTE: A refrigerant leak in the high pressure
side of the system may be more easily detected
when, if possible, the system is in operation. A
leak on the low pressure side may be most
easily detected after the engine has been shut
off for several minutes to allow system pres­
sures to equalize. This particularly applies to
the front seal.
VACUUM PUMP
A vacuum pump should be used for evacuating air and
moisture from the air conditioning system.
Vacuum pump, Tool J-5428, (fig. 26) is available for
this purpose. It is used as a component part of the
Charging Station J-8393, described previously. The fol­
lowing precautions should be observed relative to the
operation and maintenance of this pump.
• Make sure dust cap on discharge outlet of vacuum
pump is removed before operating.
• Keep all openings capped when not in use to avoid
moisture being drawn into the system.
• Oil should be changed after every 250 hours of nor­
mal operation.
To change oil, simply unscrew hex nut located on back
side of pump, tilt backward and drain out oil (fig. 26).
Recharge with ounces of vacuum pump oil Frigidaire
8
150 or equivalent (fig. 26). If you desire to flush out the
pump, use this same type clean oil. Do not use solvent.
NOTE: Improper lubrication will shorten the
life of pump.
• If this pump is subjected to extreme or prolonged
cold, allow it to remain indoors until oil has reached
approximate room temperature.
oil will result in a blown fuse.
• A five ampere time delay cartridge fuse has been
installed in the common line to protect the windings
of the compressor.
cessive load is placed on the pump. In the event the
fuse is blown, replace with a five ampere time delay
fuse - do not use a substitute fuse as it will result in
damage to the starting windings.
• If the pump is being utilized to evacuate a bumt-out
Failure to warm
The fuse will blow if an ex­
CHEVROLET TRUCK SERVICE MANUAL