COllector
can
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24-36 AIR-CONDITIONING-Service Adjustment Procedures
D&ARG,NG THE SYSTEM
Since the air conditioning refrigerant system is pressurized, it will
be necessary to completely discharge the system (in a well ven-
tilated area) before replacing any refrigerant component. The pro-
cedure is as follows:
(1) Install manifold gauge set. Make sure the gauge set valves are
closed before attaching the hoses to the refrigerant system.
(2) Install a long hose to the manifold gauge set connector. Run
this hose to the oil collector can near a shop exhaust system.
A good oil collector can may be made from a large empty
coffee can with a plastic top. Slit the plastic top in the form of
a Y to make an entrance for the refrigerant hose and an exit for
the gas.
(3) Open the compressor discharge and suction line pressure
valves and blow the refrigerant into the oil collect can. Watch
to make sure the hose does not blow out of the collector can.
(4) When the system has been completely discharged, measure
the amount of oil collected in the can. The amount of oil mea-
sured should be added to the refrigerant system before it is
re-charged. Add new oil-discard the used oil.
Caution
It is important to have the correct amount of oil in the refrig-
erant system.
Too little oil will provide inadequate compressor lubrication and
cause a compressor failure. Too much oil will increase discharge
air temperature.
When a 6P148 compressor is installed at the factory, it
contains 110 c.c. (3.7 U.S.fl.oz., 3.9 Imp.fl.oz.) of refrigerant oil.
While the air conditioning system is in operation, the oil is
carried through the entire system by the refrigerant. Some of
this oil will be trapped and retained in various parts of the
system.
When the following system components are changed, it is nec-
essary to add oil to the system to replace the oil being removed
with the component.
Compressor - 4Occ (1.4 U.S.fl.oz., 1.4 Imp.fl.oz.)
Condenser - 30 cc (1.0 U.S.fl.oz., 1.1 Imp.fl.oz.)
Evaporator - 60 cc (2.0 U.S.fl.oz., 2.1 Imp.fl.oz.)
Piping - 10 cc (.3 U.S.fl.oz., .4 Imp.fl.oz.)
Receiver drier - 0 cc (0 U.S.fl.oz., 0 Imp.fl.oz.)
EVACUATING THE SYSTEM
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Whenever the system has been opened to the atmosphere, it is
absolutely essential that the system be evacuated or “vacuumed”
to remove all the air and moisture. Air in the refrigerant system
causes high compressor discharge pressures, a loss in system
performance, and oxidation of the compressor oil into gum and
varnish. Moisture in the refrigerant system can cause the expan-
sion valve to malfunction. Under certain conditions, water can
react with the refrigerant to form destructive acids. It is necessary
to adhere to the following procedure to keep air and moisture out
of the system.
(1) Install manifold gauge set. Make sure the gauge set valves are
closed before attaching the hoses to the refrigerant system.
(2) Discharge the system if the manifold gauge set indicates pres-
sure in the system.
(3) Connect a long test hoses from gauge set manifold center
connection to vacuum pump.
(4) Open both manifold gauge set valves.
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AIR-CONDITION1 G-Service Adjustment Procedures 24-37
water 2OUO326
(5) Start the vacuum pump and operate until the evaporator suc-
tion gauge registers at least-101 kPa (29.9 in.of vacuum).
If at least-101 kPa (29.9 in. of vacuum) cannot be obtained,
either the system has a leak or the vacuum pump is defective.
Check the vacuum pump. If the pump proves to be functioning
properly, the system has a leak. Charge the system with one
pound of refrigerant. Locate and repair all leaks. Discharge the
refrigerant and evacuate the system.
(6) Continue to operate the pump for at least five minutes.
(7) Close manifold valves. Turn off the vacuum pump and observe
evaporator suction gauge for two minutes. The vacuum level
should remain constant.
If the vacuum level falls off, the system has a leak. Charge the
system with one pound of refrigerant. Locate and repair all
leaks. Discharge the system and repeat evacuation procedure.
CHARGING THE SYSTEM
The refrigerant system must have been evacuated using the pre-
vious procedure before charging. Charge using only R-l 2 refriger-
ant R-l 2 is available in bulk tanks or small cans. Follow the safety
precautions for handling R-12 as listed in the beginning of this
group.
Charging with Small Cans
When using disposable cans of this type, follow carefully the can
manufactures instructions.
Caution
Never use these cans to charge into the high pressure side of
the system (compressor discharge port) or into a system that
is at high temperature, because the high system pressures
could be transferred into the charging can causing it to ex-
plode.
Keep the refrigerant manifold valves capped when not in use.
Keep a supply of extra refrigerant-can-to-refrigerant-manifold gas-
kets on hand so that gaskets can be replaced periodically. This will
insure a good seal without excessive tightening of the can or the
manifold nuts.
(1) Attach center hose from manifold gauge set to refrigerant
dispensing manifold. Turn refrigerant manifold valves com-
pletely counterclockwise so they are fully open. Remove pro-
tective caps from refrigerant manifold.
(2) Screw refrigerant cans into manifold. Be sure manifold-to-can
gasket is in place and in good condition. Tighten can and man-
ifold nuts to 8 to 11 Nm (6 to 8 ft.lbs.)
(3) Turn refrigerant manifold valves completely clockwise to
puncture the cans and close the manifold valves.
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