Section III: TROUBLESHOOTING

TM 5-4120-352-14

TROUBLESHOOTING

Section III.

Operator's Troubleshooting

3-6.

3-5.

General.

Chart.

This section contains information that is useful

Troubleshooting procedures for operator-crew

in diagnosing and correcting troubles which cause

are listed in table 3-2.

unsatisfactory operation or failure of the air

conditioner.

Table 3-2. Troubleshooting

Malfunction

Test or Inspection

Corrective Action

1. AIR CONDITIONER FAILS TO OPERATE

Step 1. Check to see if main power cord is plugged in.

Connect power cable to receptacle (fig. 2-3, Sheet 1), supplying 208 VAC, 3 phase, 50-60 hz power.

Step 2. Check to see if compressor circuit breaker is in OFF position.

Reset circuit breaker (fig. 2-3, Sheet 1).

Step 3. Check to see if mode selector switch is in OFF position.

Turn selector switch to desired operation (fig. 2-3, Sheet 1).

2. INSUFFICIENT COOLING

Step 1. Check to see if mode selector switch is in proper position.

Set switch to COOL (fig. 2-3, Sheet 1).

Step 2. Check to see if temperature selector switch is in correct position.

Adjust setting to COOLER (fig. 2-3, Sheet 1).

Step 3. Check to see if sufficient air is passing over evaporator coil.

Open evaporator inlet louvers (fig. 2-4). Remove any obstructions from evaporator inlet and outlet

louvers.

Step 4. Check to see if too much outside air is entering unit.

Close or adjust vent (fig. 2-3, Sheet 2).

Step 5. Check to see if the system contains sufficient refrigerant by inspecting liquid sight indicator (para 3-10).

Report low refrigerant condition to direct support maintenance.

Step 6. Check to see if evaporator fan speed switch is set to LOW speed position.

Reset switch to HIGH speed position (fig. 2-3, Sheet 1).

Step 7. Check to see if sufficient air is passing through condenser coil.

Remove any obstructions from condenser fan inlet and outlet.

3. NO HEAT OR LOW CAPACITY HEAT

Step 1. Check to see if mode selector switch is properly set.

Set switch to LOW HEAT or HIGH HEAT (fig. 2-3 Sheet 1).

Step 2. Check to see if temperature selector switch is set correctly.

Adjust to WARMER setting (fig. 2-3, Sheet 1).

Step 3. Check for insufficient air movement over heaters.

Remove any obstructions from evaporator air intake and discharge louvers. Make sure intake louvers

are open (fig. 2-3, Sheet 2).

3-2