Chevrolet Light Duty Truck 1973, Service Manual

Page: 67 / 979

HEATER A N D AIR C O N D I T I O N I N G 1A-41
resulting in improper operating temperature and
pressures and decreased efficiency of the system.
CAUTIO N:
The following general practices
should be observed to ensure chemical stability
in the system:
•
Whenever it becomes necessary to disconnect a
refrigerant or gauge line, it should be immediately
capped. Capping the tubing will also prevent dirt
and foreign matter from entering.
• Tools should be kept clean and dry. This also
includes the gauge set and replacement parts.
• When adding oil, the container should be exception­
ally clean and dry due to the fact that the
refrigeration oil in the container is as moisture-free
as it is possible to make it; therefore, it will quickly
absorb any moisture with which it comes in contact.
For this same reason the oil container should not be
opened until ready for use and then it should be
capped immediately after use.
• When it is necessary to open a system, have
everything you will need ready and handy so that as
little time as possible will be required to perform
the operation. Don’t leave the system open any
longer than is necessary.
• Finally, after the operation has been completed and
the system sealed again, air and moisture should be
evacuated from the system before recharging.
J-8393 CHARGING STATION
LOW PRESSURE
CONTROL ( l)
VACUUM
CONTROL
(3)
HIGH PRESSURE
CONTROL ( 2)
LOW PRESSURE
GAUGE LINE
REFRIGERANT
CONTROL
(4)
HiGH PRESSURE
GAUGE LINE
5 LB. CHARGING
' CYLINDER
-LEAK
DETECTOR
REFRIGERANT
•CONTROL VALVE
Fig. 4 5 -J-8393 Charging Station
use. Thus a current air conditioning dealer can use the
equipment on hand and avoid duplication.
The J-8393 Charging Station is a portable assembly of a
vacuum pump, refrigerant supply, gauges, valves, and
most important, a five (5) pound metering refrigerant
charging cylinder. The use of a charging cylinder
eliminates the need for scales, hot water pails, etc.
The chief advantage of this unit is savings. A very
definite savings in refrigerant and time can be obtained
by using this unit. Since the refrigerant is metered into
the system by volume, the correct amount may be added
to the system. This, coupled with the fact that the unit
remains "plumbed" at all times and thus eliminates loss
of refrigerant in purging of lines and hooking-up,
combines to enable the operator to get full use of all
refrigerant purchased.
All evacuation and charging equipment is hooked
together in a compact portable unit (fig. 45). It brings air
conditioning service down to the basic problem of
hooking on two hoses, and manipulating clearly labeled
valves.
This will tend to ensure that the job will be done without
skipping operations. As a result, you can expect to save
time and get higher quality work, less chance of an over
or under charge, thus reducing comebacks.
The pump mount is such that the dealer may use his own
vacuum pump. The gauges and manifold are in common
GAUGE SET
The gauge set (fig. 46) is an integral part of the J-8393
Charging Station. It is used when purging, evacuating,
charging or diagnosing trouble in the system. The gauge
at the left is known as the low pressure gauge. The face
is graduated into pounds of pressure and, in the opposite
Fig. 46 -Gauge Set
1
LOW PRESSURE
CONTROL
2
HIGH PRESSURE
CONTROL
3
VACUUM
CONTROL
4
REFRIGERANT
CONTROL
LIGHT DUTY TRUCK SERVICE MANUAL