3-13. OPERATIONAL CHECK. - Continued.
l. The temperature control thermostat has an effective functional range between 60 and 90F (15 and 32C). In
extreme conditions when ambient air temperature is below 60F (15C) or above 90F (32C), operation in HEAT mode
will vary from that described above.
m. Turn temperature control thermostat knob to fully WARM (clockwise) position, then turn mode selector switch to
COOL. Hold your hand in air flow from conditioned air louver; there should be no change in temperature. Now turn
temperature control thermostat knob to fully COOL (counterclockwise) position and feel outlet air temperature begin to
drop almost immediately. Leave controls in present position and perform next check.
n. After 15 minutes of operation, examine sight glass and check refrigerant condition.
o. Turn mode selector switch to OFF/RESET and observe that all air conditioner functions cease.
p. Set-up the air conditioner for the desired operational mode.
Section IV. UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
3-14. 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 prevent ive 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 very dusty or sandy environment, it may be necessary to reduce the interval to monthly or even less if conditions are
c. Table 3-2 lists the unit preventive maintenance checks and ser vices 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 minimum amount of required maintenance downtime.