UNIT TROUBLESHOOTING INTRODUCTION - TM-9-4120-425-14-P0073

TM 9-4120-425-14&P

UNIT TROUBLESHOOTING INTRODUCTION

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MALFUNCTION/SYMPTOM INDEX

The malfunction/symptom index (WP 0009-00) is a quick reference index for finding troubleshooting procedures.

Associated with each symptom name is a work package sequence number representing the starting point in a

troubleshooting sequence. Should any one symptom require more than one troubleshooting sequence to arrive at the

most likely area of investigation, the additional starting point numbers are presented.

As the troubleshooting activity progresses through to the conclusion of a particular sequence, a reference is made to the

next logical troubleshooting sequence by work package sequence number or by referring to the malfunction/ symptom

index to locate the next failure symptom work package. This type of activity continues until successful fault isolation is

achieved.

TROUBLESHOOTING PROCEDURES

The troubleshooting work packages contain tables listing the malfunctions, tests or inspections, and corrective

action required to return the air conditioner to normal operation. Perform the steps in the order they appear in the

tables.

Each work package is headed by an initial setup. This setup outlines what is needed as well as certain conditions which

must be met before starting the task. DON'T START A TASK UNTIL:

Check the power source voltage and phase.

You understand the task.

You understand what you are to do.

You understand what is needed to do the work.

You have the things you need.

This manual cannot list all malfunctions that may occur, or all tests or inspections and corrective actions. If a

malfunction is not listed or is not corrected by listed corrective actions, notify unit maintenance.

GENERAL INFORMATION

Fan and Compressor Motor Lubricants

Motors driving the evaporator/condenser fan and compressor are permanently lubricated. The compressor is a sealed unit

complete with lubricant. The rotating parts do not need any lubrication.

Mechanical Lubrication

The only mechanical items which may require lubrication are the conditioned air supply and return louvers, the

condenser air discharge louver and control linkages. These points should be checked and lubricated, as necessary, during

preventive maintenance service. A few drops of light oil should be applied to pivot points, bearing surfaces, and linkages

to prevent or eliminate stiffness or binding. Be sure to wipe off all excess oil with a cloth or paper towel. These items are

in an area of high volume air flow and excess oil will tend to attract and accumulate dust particles from the passing air.

Graphite may be used as an alternate lubricant during extreme cold weather operation.

END OF TASK

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