TABLE 4-2. TROUBLESHOOTING - continued

TM5-4120-347-14

TABLE 4-2. TROUBLESHOOTING (cont.)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 3.

Inspect condenser fan for damage

Replace fan. (Refer to paragraph 4-43.)

Step 4.

Make sure that air outlet louvers are not stuck or jammed in closed position.

Free louvers and control cable. Adjust control, or report to direct support maintenance if

actuating cylinder is not working properly.

9. AIR CONDITIONER FAILS TO HEAT.

Check selector switch for improper setting.

Step 1.

Set selector switch to LOW HEAT or HIGH HEAT.

Make sure that temperature control switch is set properly.

Step 2.

Reset switch, if necessary.

Step 3.

Check for dirty evaporator return air filter.

Clean filter.

Step 4.

Check evaporator fan motor for proper operation,

Replace bad motor. (Refer to paragraph 4-40.)

Step 5.

Make continuity check of temperature selector switch or mode selector switch.

Replace bad switch. (Refer to paragraphs 4-28 and 4-30.)

Inspect heaters and wiring for loose connections or damage.

Step 6.

Tighten connections and fix bad wiring. Replace bad heater elements. (Refer to paragraph

4-42.)

Check continuity of heater relay coils.

Step 7.

Replace bad relay. (Refer to paragraph 4-35.)

Check operation of heater high-temperature cutout thermostatic switch. It should open when

Step 8.

temperature rises above setting.

Replace bad thermostatic switch. (Refer to paragraph 4-41.)

10. EXCESSIVE NOISE.

Step 1.

Check evaporator or condenser fan for vibration.

Tighten fans on shafts. Tighten all mounting screws.

Check evaporator or condenser fan motor for wear, as indicated by noisy operation or

Step 2.

excessive side or end play.

Replace worn or bad motor. (Refer to paragraphs 4-40 and 4-43.) (Refer to direct support

maintenance for repairs.)

Step 3.

Listen for compressor knocks or chatter.

Stop air conditioner and report condition to direct support maintenance.

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