ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
Return Air Filter. Install filter (2) and tighten two captive fasteners (1) (see fig. 4-11).
Figure 4-11. Return Air Filter Installation
Section IV. UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
4.13 GENERAL. The Preventive Maintenance Checks and Services (PMCS) are defined in the following paragraphs.
a. Systematic, periodic, preventive maintenance checks and services 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 4-1 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.
4.14 PMCS COLUMNAR ENTRIES. The PMCS table column headings and column entries are defined in the following
a. "Item Number" Column. This is the order in which you perform checks and services on the air conditioner. The
entry in this column will also be used as a source of item numbers for the' "TM Item Number" column in DA Form
2404, Equipment Inspection and Maintenance Worksheet, in recording results of PMCS.
b. "Interval" Column. The interval column tells you when to do a certain check or service.
c. "Item To Check/Service" Column. Identification of item to be inspected.