Table 4-2. Troubleshooting - TM-5-4120-352-140037

TM 5-4120-352-14

Table 4-2. Troubleshooting

Malfunction

Test or Inspection

Corrective Action

1. AIR CONDITIONER FAILS TO OPERATE

Step 1. Check to see if main power cable is connected.

Connect cable to power source.

Step 2. Check to see if main power receptacle is defective.

Tighten loose connections.

Step 4. Check to see if mode selector rotary switch is improperly positioned or is defective.

Turn selector to COOL or VENT. Replace switch if defective (para 4-42).

Step 5. Check to see if control circuit breaker or compressor circuit breaker is in OFF position or is defective.

Reset circuit breaker(s) or replace defective circuit breaker (para 4-42).

Step 6. Test control circuit transformer and rectifier for faulty operation.

Replace defective transformer and/or rectifier (para 4-45 and 4-46).

2. INSUFFICIENT COOLING

Step 1. Check to see if the mode selector switch is improperly positioned.

Set switch to COOL.

Step 2. Check to see if temperature selector control is improperly positioned or is defective.

Adjust setting or replace switch (para 4-42).

Step 3. Check to see if fresh air damper control is incorrectly set or improperly adjusted.

Verify setting and, if necessary, correct adjustment of damper control (para 4-27).

Step 4. Check to see if evaporator outlet louver is bent of stuck in closed position.

Repair or replace louver (para 4-18).

Step 5. Inspect condenser coil for dirt accumulation.

Clean coil (para 4-23).

Step 6. Inspect evaporator return air filter for dirt accumulation.

Clean filter (para 4-17).

Step 7. Check to see if evaporator fan is loose or defective.

Tighten if loose or replace if defective.

Step 8. Check evaporator fan motor for a defective thermal protective device.

Replace thermal protector (para 4-39).

Step 9. Check to see if evaporator fan motor is worn or defective.

Report deficiency to direct support maintenance or replace motor (para 4-38 and 4-40).

Step 10. Test refrigerant system for insufficient charge by inspecting liquid sight indicator.

Report low-charge condition to direct support maintenance.

Step 11. Check compressor for defective operation.

Report condition to general support maintenance

3. EVAPORATOR OR CONDENSER FAN FAILS TO OPERATE

Step 1. Check to see if main power cable is connected.

Connect cable to power source.

Step 2. Check to see if main power receptacle or plug connectors are defective.

Replace connectors or receptacle (para 4-33).

Step 3. Check to see if mode selector rotary switch is improperly adjusted or is defective.

Replace switch if defective (para 4-42).

Step 4. Check to see if evaporator fan speed control switch is defective.

Replace defective switch (para 4-42).

Step 5. Check to ace if condenser fan motor thermal protector is defective.

Replace defective thermal protector (para 4-39).

Step 6. Check to see if evaporator fan motor thermal protector is defective.

Replace defective thermal protector (para 4-39).

4-3