AIR CONDITIONING SYSTEM TROUBLESHOOTING AND TESTING

TM 9-2320-303-24-1

AIR CONDITIONING SYSTEM TROUBLESHOOTING AND TESTING

THIS WORK PACKAGE COVERS

Preliminary Checks, Performance Tests, Safety Precautions, Air Conditioning Troubleshooting

INITIAL SETUP

Tools and Special Tools - Continued

Maintenance Level

Goggles (Item 30, WP 0313 00)

Unit

Leak detector (Item 54, WP 0313 00)

Tools and Special Tools

Tool kit, general mechanic's (Item 102, WP 0313

Gloves (Item 27, WP 0313 00)

PRELIMINARY CHECKS

Before testing the operation of the air conditioning system, make the following checks:

Make sure the refrigerant compressor's drive belt is not damaged and is correctly tensioned. Also check the compressor

mountings for tightness.

Check for broken, burst, or cut hoses; also check for loose fittings on all parts.

Check for road debris build-up on the condenser coil fins. Using air pressure and a whiskbroom or a soapy spray of

water, carefully clean off the condenser; be careful not to bend the fins.

Check the color of the moisture indicator sight glass. If the color is a deep cobalt blue, the refrigerant charge is dry.

If the indicator is not blue, the system is contaminated with moisture. Notify your supervisor.

If there is not enough airflow, make sure that leaves or other debris has not entered the fresh air ports under the

windshield. If debris has entered, it could clog the fins of the evaporator core, and block airflow. Also, be sure that

all ducts are connected to the dash louvers and that the air-control flaps in the heater housing are moving properly

(this requires removal of the right and center dash panel).

PERFORMANCE TESTS

Following is a brief description of symptoms or conditions that could exist if something goes wrong with a refrigerant

part.

Receiver-Drier.

The receiver-drier is normally at outside temperature. To the touch, the entire length of the unit should be the same

temperature. If noticeable cool spots exist, notify your supervisor.

A blockage at the inlet of the unit will cause high head pressures; outlet blockages will cause low head pressures

and little or no cooling.

If the moisture indicator is pink or white (showing that the system is wet), the receiver-drier is saturated with mois-

ture and must be replaced. Notify your supervisor.