TM 9-4120-403-14
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 4-1 lists the unit preventive maintenance checks and services that should be performed at quarterly
intervals (or otherwise stated in table 4-1). 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.
WARNING
Voltages used can kill. Always disconnect power cord to air conditioner before performing any internal
maintenance. Shutting unit off at its control panel does not disconnect unit power.
4-8
