TM 9-4120-385-14
Table 42. TROUBLESHOOTING FOR UNIT MAINTENANCE
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 6. Refer to wiring diagram (FO-1). Check for broken and loose connections.
Repair or replace as necessary. Refer to Paragraph 423.
3. LlTTLE OR NO HEATING IN LOW HEAT MODE
Step 1. Check that controls are properly positioned for LO HEAT operation
Position controls for LO heat operation.
Step 2. Check for air movement out of air outlet louver and into return air inlet.
NOTE
This unit can operate in temperatures as low as 50F (10 C). However, depending on
shelter or van size, heat loss, and amount of heat generated by equipment, heat output
in the LO HEAT mode may or may not heat shelter or van to a comfortable level.
Remove obstructions from air inlets/outlets.
q
Clean return air filter. Refer to Paragraph 4-15.
q
Clean mist eliminator. Refer to Paragraph 4-16.
q
Step 3. Compare discharge air temperature to return air temperature by:
Turn mode selector switch to LO HEAT and temperature selector to maximum
q
INCREASE.
After operating for 5 minutes, measure return air temperature and discharge air
q
temperature.
NOTE
Discharge air temperature should be at least 10F (12.2C) above return air temperature.
