|
| |
solenoid valve is open during the bypass cycle of
operation and closed during the cooling cycle of
operation. When testing these valves for proper
operation, determine which cycle of operation
(bypass or cooling) the unit is in, and test opera-
tion of valves accordingly.
b. Removal. Remove the valves (para 5-16).
c. Disassembly.
(1) Refer to figure 6-6 and disassemble the
valves.
Section III. EVAPORATOR
6-6. Evaporator Coil
a. Removal. Remove the evaporator coil (para
5-20) .
b. Cleaning, Inspection, and Repair,
(1) Clean the coil area with a wire brush.
Avoid damage to the fins during brushing. Blow
coil with compressed air.
(2) Inspect the coil for bent fins, damaged
coil runs, and internal leaks.
(3) Straighten the fins with needle nosed
pliers. Replace a coil with damaged coil runs or
internal leaks.
(2) Disconnect tubing from body.
d. Repair. Replace unserviceable parts with
serviceable like parts.
e. Reassembly.
(1) Solder tubing to body.
(2) Reassemble the valves by reversing the
order of disassembly.
f. Installation. Install the valves (para 5-16).
AND CONDENSER
c. Installation.
(para 5-20).
COILS
Install the evaporator coil
6-7. Condenser Coil
a. Removal. Remove the condenser coil (para
5-21).
b. Cleaning, Inspection, and Repair. Clean,
inspect, and repair the condenser coil in the same
manner as outlined in paragraph 6-6.
c. Installation. Install the condenser coil (para
5-21).
Section IV. COMPRESSOR/MOTOR ASSEMBLY AND BURNOUT
CLEANUP PROCEDURES
6–8. Compressor/Motor
a. General. The compressor motor is hermeti-
cally sealed and not repairable. An inoperative
compressor is usually due to a mechanical failure
causing the compressor to freeze, a control fail-
ure, or a motor burnout. If the compressor has
been mechanically frozen there may be a burnout.
If so, the compressor unit must be replaced.
When the motor of a hermetically sealed unit fails,
high temperatures may develop within the com-
pressor causing a breakdown of the oil or re-
frigerant, resulting in formation of moisture,
acid, and sludge, all extremely harmful to the
air conditioner. Repeated burnouts may occur if
contaminants are not completely removed. Refer
to paragraph 6-9 for burnout cleanup procedures.
The compressor has a suction line filter strainer to
prevent damage to the compressor from contami-
nation. If ‘a compressor/motor unit fails to operate
check the compressor motor for resistance as
outlined in b. below.
b. Resistance Measurements.
(1) Model CH-620-1.
(a) Remove the front access panel (para
3-6)
(b) Check the terminal’ to terminal res-
istance (A to B, B to C, and C to A) with a multi-
meter set on the ohm scale. Proper resistance is
1.37 ohms at 25° C. Tolerance is ± 7 percent.
(c) Replace the front access panel (para
3-6 ).
(2) Model CH-420-1.
(a) Remove the front access panel (para
3-6).
(b) Check the terminal to terminal resist-
ance as indicated in (1) (b) above. Reading
should be 0.387 ohms at 250 C. with a tolerance
of ± 7 percent.
(c) Replace the front access panel (para
3-6) .
6-9. Compressor/Motor Burnout Cleanup
Procedure
a. General.
(1) The scope of this procedure pertains
hermetic compressors.
to
(2) Experience has demonstrated that after
a hermetic motor burnout the system must be
cleaned thoroughly to remove all contaminants;
otherwise a repeat burnout will occur. Failure to
follow these instructions as quickly as possible
will result in an excessive risk of a repeat bur-
nout, and damage to other system components.
b. Cleanup Procedure, Make certain a burnout
6-8
|
