TM 9-4120-371-14
Section IV UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
4-16. INTRODUCTION, INSPECTION, AND
SERVICE
a. Systematic, periodic, Preventive Maintenance Checks and Services (PMCS) are essential to ensure that
the air conditioner is ready for operation at all times. The purpose of a preventive maintenance program is to
discover and correct defects and deficiencies before they can cause serious damage or complete failure of the
equipment. Any effective preventive maintenance program must begin with the indoctrination of operators to
report all unusual conditions noted during daily checks or actual operation to unit maintenance. All defects and
deficiencies discovered during maintenance inspections must be recorded, together with corrective action
taken, on DA Form 2404 (Equipment Inspection and Maintenance Worksheet).
b. A schedule for unit preventive maintenance inspection and service should be established immediately
after installation of the air conditioner. A quarterly interval, equal to three calendar months or 250 hours of
operation (whichever occurs first) is recommended for usual operating conditions. When operating under
unusual conditions, such as a very dusty or sandy environment, it may be necessary to reduce the interval to
monthly or even less if conditions are extreme.
c. Table 41 lists the unit preventive maintenance checks and services that should be performed at
quarterly (or otherwise established) intervals. The PMCS items in the table have been arranged and numbered
in a logical sequence to provide for greater personnel efficiency and least amount of required maintenance
downtime.
Disconnect input power before disassembly of the air conditioner for PMCS to prevent
dangerous, possibly fatal, electrical shock.