TM 9-4120-402-14
Table 4-2. Unit Preventive Maintenance Checks and Services (PMCS)
Quarterly Schedule - continued
Item
Item to be
Procedures
Paragraph
Number
Inspected/Serviced
Reference
CAUTION
Use suitable disconnect to isolate power
source when connecting input power cable.
Do not connect power cable to unit or power
source if voltage is present.
23
Operation Checks
a.
Be sure the MODE selector rotary switch is in the
OFF/RESET position and reconnect input power.
CAUTION
Do not check operation in COOL mode until
after input power has been reconnected for a
sufficient time to eliminate any danger of liquid
refrigerant accumulation in the compressor.
Except in extremely cold conditions, if input
power has been disconnected for a period of
less than six hours, an equal warm-up period
should be allowed. If the disconnected period
has been more than six hours, a full six hour
warm-up period is necessary.
b. Check that the fabric cover is rolled up and secured.
c. Adjust conditioned air intake and outlet louvers to the full
open position.
d. Adjust fresh air damper to full closed position.
e. Turn MODE selector rotary switch to VENTilate. After a
short delay (approximately five seconds), the fan should
start.
f. Use a paper streamer or smoke and note amount of air
being discharged from conditioned air outlet grille.
g. Open fresh air damper fully.
h. Close conditioned air intake grille louvers fully.
i. Again check air flow as in step f. above. Air flow should be
approximately the same.
j. Fully open louvers in conditioned air intake grille and fully
close fresh air damper.
4-35
