|
| |
Section V. TROUBLESHOOTING
4-11. General
This section contains troubleshooting instructions
for the isolation of causes of common troubles that
may occur during operation and also contains the
possible remedies to correct the trouble.
4-12. Organizational Troubleshooting Chart
a. General. Troubleshooting procedures for
organizational maintenance personnel are listed in
table 4-2. The first column shows the apparent
trouble or symptom. The second column contains
the probable cause. The third column lists the
corrective action to be taken. Remedies that are
beyond the scope of organizational maintenance
must be reported to direct support maintenance
personnel. Additional procedures are listed in
paragraph b and c below.
b. Control Circuit. The cause for a system’s
failure to operate can be greatly narrowed if the
control which caused the failure can be isolated. It
Malfunction
1. Air conditioner fails to operate.
2. Insufficient cooling.
is the function of safety devices to open the circuit
under certain conditions; therefore, additional
checking may be required to determine whether the
safety device is open because it is defective or is
performing its designed function. The following
steps contain instructions for checking the control
circuit.
(1) Disconnect power from air conditioner.
(2) Test the continuity across each control in
the affected circuit with a test lamp or ohmmeter if
available using schematic diagrams as a guide.
Check wiring diagrams for connections.
(3) Replace defective parts.
c. Safety Devices. When testing the control
circuit and other equipment, take into con-
sideration the fact that open safety devices may not
be defective. It may be normal for the device to be
open under the existing conditions or it may in-
dicate trouble elsewhere in the’ air conditioner.
Table 4-2. Troubleshooting Chart
Probable Cause
a. Main power cable disconnected.
b. Main power receptacle connector
defective.
c. Loose electrical connections.
d. Rotary selector switch improperly
adjusted or defective.
e. Control or compresser circuit
breaker in OFF position or
defective.
f. Defective phase, sensing relay.
g. Defective control circuit trans-
former.
h. Defective control circuit rectifier.
a. Mode selector switch improperly
positioned.
b. Insufficient refrigerant charge.
c. Condenser coil dirty.
d. Evaporator return air filter dirty.
e. Temperature selector switch set
incorrectly or defective.
f. Fresh air damper control set in-
correctly or incorrectly adjusted.
g. Defective compressor.
h. Evaporator outlet louver bent or
stuck in closed position.
i. Evaporator fan motot worn or
defective.
j. Evaporator fan loose or defective.
k. Evaporator fan motor thermal
protector defective.
Corrective Action
a. Connect cable.
b. Replace connector (para 4-33).
c. Tighten connections.
d. Turn selector switch to “COOL"
or “VENTILATE". Replace a
defective switch (para 4-44
through 4-48).
e. Reset circuit breaker(s) or replace
(para 4-44 thru 4-48 or para 4-50
thru 4-54).
f. Replace defective phase sensing
relay (para 4-50 thru 4-.54).
g. Replace defective transformer
(para 4-56).
h. Replace defective rectifier (para 4-
57).
a. Set switch to “COOL".
b. Report condition to direct support
maintenance.
c. Clean coil (para 4-23).
d. Clean filter (para 4-17).
e. Adjust setting or replace switch
(para 4-44 thru 4-48).
f. Check setting of Control. Adjust
fresh air damper control (para 4-
27).
g. Report condition to general
support maintenance.
h. Repair or replace louver (para 4-
18).
i. Report deficiency to direct
support maintenance or replace
motor (para 4-38 and 4-40).
j. Tighten or replace fan.
k. Replace thermal protector (para 4-
39).
4-3
|
