i
HEATERS AND AIR CONDITIONING - Service Adjustment Procedures 24-21Hot water40°C (104°F)
1467CHARGING SYSTEM
The refrigerant system must have been evacuated using the
previous procedure before charging.
Charge using only R-l 2 refrigerant.
R-12 is available in bulk
tanks or small cans. Follow the safety precautions for handling
R-12 as listed in this group.
Charging with Small Cans
When using disposable cans of this type, follow carefully the
can manufacturers instructions.
Caution
Never use these cans to charge into the high pressure side
of the system (compressor discharge port) or into a systemthat is at high temperature, because the high system
pressures could be transferred into the charging can
causing it to explode.
Keep the refrigerant manifold valves capped when not in use.
Keep a supply of extra refrigerant-can-to-refrigerant-manifold
gaskets on hand so that gaskets can be replaced periodically.
This will insure a good seal without excessive tightening of thecan or the manifold nuts.
(1) Attach center hose from manifold gauge set to refrigerant
dispensing manifold. Turn refrigerant manifold valves com-pletely anticlockwise so they are fully open.
Remove protective 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 manifold 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.
(4) Purge the air from the charging line by loosening the
charging hose at the gauge set manifold and turning one ofthe refrigerant valves anticlockwise to release refrigerant.
When the refrigerant gas starts escaping from the loose
connection, re-tighten the hose.
Caution
Never heat small refrigerant cans over
40°C (104°F) as
they may explode.
(5) Fully open all refrigerant manifold valves being used and
place the cans of refrigerant into a pan containing
40°C
(104°F) water. The water will warm the charging can and
aid in the transfer to the charge into the system. Place the
water pan and refrigerant cans on a scale and note the
weight.
(6)Place air conditioner control on air conditioner and place theblower switch on high.
(7) Open the discharge and suction gauge valves of the gaugemanifold, and charge gas from the both.
Keep refrigerant container upright.
(8) When suction of refrigerant is saturated, close the dis-
charge and suction gauge valves once, and start the
engine. Fix the engine revolution speed at approx. 1,500
rpm.
24-22 HEATERS AND AIR CONDITIONING - Service Adjustment Procedures(9) Charge through the suction side of the system by slowly
opening the suction manifold valve. Adjust the valve as
necessary so charging pressure does not exceed 345
kPa 6(50 psi). Maintain the temperature of the water in the pan w’
by adding warm water as necessary.
Note the weight of water added, to ensure accuracy when
determining amount of refrigerant added to system.
(lO)When specified refrigerant charge Max. 925
g (32 oz.) has
entered the system, close the gauge set manifold valves,
refrigerant manifold valves, and
reconnnect wiring. Each
can contains 397
g (14 oz.) of R-l 2. Use 2 l/2 cans.
HANDLING
TUBINGANDFITTINGSLiquid line
\
IDual pressure
switch
Low pressure
Liquid lineHigh pressure hose
20A0440Kinks in the refrigerant tubing or sharp bends in the
refrigerant hose lines will greatly reduce the capac-
ity of the entire system. High pressures are pro-
duced in the system when it is operating. Extreme
care must be exercised to make sure that all
connections are pressure tight. Dirt and moisture
can enter the system when it is opened for repair or
replacement of lines or components. The following
precautions must be observed.
The system must be completely discharged before
opening any fitting of connection in the refrigeration
system. Open fittings with caution even after the
system has been discharged. If any pressure is
noticed as a fitting is loosened, allow trapped
pressure to bleed off very slowly.Never attempt to rebend formed lines to fit. Use the
correct line for the installation you are servicing.
A good rule for the flexible hose lines is keep the
radius of all bends at least 10 times the diameter of
the hose.
Sharper bends will reduce the flow of refrigerant.
The flexible hose lines should be routed so that they
are at least 80 mm (3 in.) from the exhaust manifold.
It is good practice to inspect all flexible hose lines atleast once a year to make sure they are in good
condition and properly routed.
Unified plumbing connections with O-rings. These
O-rings are not reusable.
