Chevrolet 10 Series 1968, Руководство по обслуживанию

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HEATER AND AIR CONDITIONING 1A-15
possible to make it. Therefore, it will quickly ab­
sorb 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 every­
thing 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
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 elim ­
inates 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 and charged to the customer. 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 by the
dealership.
A ll evacuation and charging equipment is hooked to­
gether in a compact portable unit (fig. 26). It brings air
conditioning service down to the basic problem of hooking
on two hoses, and manipulating clearly labeled valves.
This will tend to insure 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 undercharge, or comeback.
The pump mount is such that the dealer may use his
own vacuum pump. The gauges and manifold are in com­
mon use. Thus a current air conditioning dealer can use
the equipment on hand and avoid duplication.
GAUGE SET
The gauge set (fig. 27) is an integral part of the
J-8393 Charging Station. It is used when purging, evac­
uating, 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 direction, in inches of vacuum. This is the
gauge that should always be used in checking pressures
on the low pressure side of the system. When all parts of
the system are functioning properly the refrigerant
pressure on the low pressure side never falls below 0
pounds pressure. However, several abnormal conditions
can occur that will cause the low pressure to fall into a
partial vacuum. Therefore, a low pressure gauge is
required.
The high pressure gauge is used for checking pres­
sures on the high pressure side of the system.
The hand shutoff valves on the gauge manifold do not
control the opening or closing off of pressure to the
gauges. They merely close each opening to the center
connector and to each other. During most diagnosing
and service operation, the valves must be closed. The
only occasion for opening both at the same time would be
to bypass refrigerant vapor from the high pressure to
the low pressure side of the system, or in evacuating
both sides of the system.
The charging station provides two flexible lines for
connecting the gauge set to the system components.
VACUUM PUMP
A vacuum pump should be used for evacuating air and
moisture from the air conditioning system.
HIGH PRESSURE
CONTROL (2) LOW PRESSURE
CONTROL
FREON
CONTROL
(
4
)
HIGH PRESSURE
GAUGE LINE
5 LB. CHARGING
CYLINDER
LEAK
DETECTOR
FREON DRUM
CONTROL VALVE
VACUUM
CONTROL
(
3
)
LOW
GAUGE LINE
1
LOW PRESSURE
CONTROL
3
VACUUM
CONTROL
2
HIGH PRESSURE
CONTROL
4
FREON
CONTROL
F ig . 26—J-8 3 9 3 C h argin g Station Fig. 27—Charging Station G auge Set
CHEVROLET TRUCK SERVICE MANUAL