Chevrolet 10 Series 1968, Service Manual

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HEATER AND AIR CONDITIONING 1A-13
F ig . 24—A ir Conditioning System Components—Typ ical (1 0 -30 Series Shown)
GENERAL INFORMATION
In any vocation or trade, there are established proce­
dures and practices that have been developed after many
years of experience. In addition, occupation hazards
may be present that require the observation of certain
precautions or use of special tools and equipment. Ob­
serving the procedures, practices and precautions of
servicing refrigeration equipment will greatly reduce the
possibilities of damage to the customers’ equipment as
well as virtually eliminate the element of hazard to the
serviceman.
PRECAUTIONS IN HANDLING REFRIGERANT-12
Refrigerant-12 is transparent and colorless in both the
gaseous and liquid state. It has a boiling point of 21.7°F
below zero and, therefore, at all normal temperatures
and pressures it will be a vapor. The vapor is heavier
than air and is noninflammable, nonexplosive, nonpoi-
sonous (except when in contact with an open flame) and
noncorrosive (except when in contact with water). The
following precautions in handling R-12 should be ob­
served at all times.
• All refrigerant drums are shipped with a heavy metal
screw cap. The purpose of the cap is to protect the
valve and safety plug from damage. It is good prac­
tice to replace the cap after each use of the drum.
® If it is ever necessary to transport or carry a drum
or can of refrigerant in a car, keep it in the luggage
compartment. Refrigerant should not be exposed to
the radiant heat from the sun since the resulting in­
crease in pressure may cause the safety plug to
release or the drum or can to burst.
• Drums or disposable cans should never be subjected
to high temperature when adding refrigerant to the
system. In most instances, heating the drum or can
is required to raise the pressure in the container;
higher than the pressure in the system during the
operation. It would be unwise to place the drum on a
gas stove, radiator or use a blow torch while pre­
paring for the charging operation, since a serious
accident could result. Don’t depend on the safety
plug - many drums have burst when the safety plug
failed. Remember, high pressure means that great
forces are being exerted against the walls of the
container. A bucket of warm water, not over 125°F,
or warm wet rags around the container is all the
heat that is required.
• Do not weld or steam clean on or near the system.
Welding or steam cleaning can result in a dangerous
pressure buildup in the system.
CHEVROLET TRUCK SERVICE MANUAL