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Page Title:
Section III. GENERAL MAINTENANCE |
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 Section III. GENERAL MAINTENANCE
NOTE
5-6. Cooling Cycle of Operation
Air conditioner is equipped with two service valves
located behind a panel at the back of the unit. These
continuously, whether the temperature control is
v a l v e s contain an integral pin which must be
calling for cooling or not, when the unit is adjusted
depressed to open the valve. Consequently the service
to operate on the cooling cycle of operation. This
hose connectors must contain a valve depressor in
order to open the air conditioner service valve when
feature
provides
a
constant
electrical
load,
which
connected.
prevents voltage fluctuations within the system.
b. By-pass Cycle of Operation. W h e n t h e
( 1 ) Remove two screws and remove the access
conditioned air temperature falls below the tem-
cover for access to service valves.
p e r a t u r e control setting, the circuit, which controls
t h e solenoid valve, is energized causing the liquid
l i n e solenoid valve to close. This stops the flow of
l i q u i d refrigerant to the evaporator coil. This stops
the cooling function completely, and by-passes a
s m a l l amount of liquid refrigerant into the suction
line through a thermostatic expansion valve.
suction pressure is maintained by hot gas by-pass
(2) Connect charging manifold to air conditioner
through the fluid pressure regulator.
service valves.
NOTE
5-7. Refrigerant Charge Checks
In accordance with Environmental Protection Agency regulations,
a. O p e r a t e u n i t c o n t i n u o u s l y f o r a m i n i m u m o f r e f r i g e r a n t s cannot be discharged into the atmosphere. A
30 minutes.
recovery/recycling unit must be used whenever
b. While unit is operating, observe the sight
glass.
c. I f r e f r i g e r a n t p a s s i n g t h r o u g h s i g h t g l a s s i s d i s c h a r g i n g t h e u n i t .
clear and cooling is being produced, it may be
assumed that the refrigerant system is adequately
Operation of the recovery/recycling unit must
charged.
be by AUTHORIZED PERSONNEL ONLY.
d. I f t h e r e f r i g e r a n t p a s s i n g t h r o u g h t h e s i g h t
g l a s s contains bubbles or appears milky, the system
(3) Connect and operate recovery/recycle unit in
may require additional refrigerant.
accordance with the manufacturer's instructions.
a. Testing for Leaks.
(1) Halide torch detector. This is the
preferred method of testing for leaks in the
c. Purging of Contaminated Refrigerant.
refrigerant system if an electronic halogen tester is
( 1 ) Remove two screws and remove the access
not available. Pass the exploring tube slowly over
cover.
a l l sweat fittings, mechanical couplings,and valves.
( 2 ) Prepare to attach a suitable discharge line
I f refrigerant is leaking from the system, the flame
to the service valve with other end of the hose in a
o f the halide torch will change from blue to green
safe area.
when the leak is small. If the leak is large, the flame
(3) Connect the hose and discharge con-
will be dense blue with a reddish tip; or a large leak
taminated
refrigerant.
may extinguish the torch. Mark all spots where
(4) Install access cover.
leaks are noticed. Discharge system (b below),
repair any leaks and pressure test (d below).
Avoid bodily contact with liquid
(2) S o a p s o l u t i o n m e t h o d . B r u s h a l l p o s s i b l e
refrigerant
and avoid inhaling of
p o i n t s of leakage with soap solution, and watch for
refrigerant gas. Be careful that
soap bubbles. Follow a definite sequence so all
Refrigerant-22 does not contact the
points will be thoroughly tested. Wipe the soap
eyes. In case of refrigerant leaks,
s o l u t i o n from all joints and mark any spot where a
ventilate area immediately.
leak occurs. Discharge the refrigerant system (b
d. Pressure Testing and Evacuating.
below).
( 1 ) The two service valves are located behind
b. Discharging Refrigerant S y s t e m .
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