TM 9-4120-407-14
(3) Turn the MODE selector rotary switch to HEAT position.
NOTE
The motor controller will take approximately two seconds to bring
the evaporator fan motor from start to full power.
(4) If the TEMPERATURE/PRESSURE FAULTS indicator light comes on, immediately turn the MODE
selector rotary switch to COOL position for one minute, then to OFF RESET position and check the
following.
NOTE
The TEMPERATURE/PRESSURE FAULTS indicator light will come
on if the evaporator discharge air temperature exceeds safe operating
limits.
(a) The evaporator air discharge grille is closed. Open if necessary.
(b) The evaporator air return grille and or the fresh air damper are closed. Open or adjust if
necessary.
EVAPORATOR AIR
DISCHARGE GRILLE
(EACH LOUVER CAN BE ADJUSTED
INDIVIDUALLY BY HAND)
EVAPORATOR AIR
RETURN GRILLE
(ADJUSTED AT HANDLE)
Figure 2-12. Grille Adjustment
(5) Turn the MODE selector rotary switch to HEAT position. If the TEMPERATURE/PRESSURE
FAULTS indicator light continues to come on, notify Unit Maintenance.
NOTE
The evaporator fan motor will continue to operate when the heating
elements cycle on and off.
(6) If the air conditioner was returned to the heating mode, the temperature should soon stabilize and
the air conditioner will begin to cycle the heating elements on and off. If the desired temperature
is not maintained, adjust the TEMPERATURE knob slightly toward WARM or COOL as necessary
until it does.
(7) When discontinuing heating mode of operation, rotate MODE selector rotary switch to VENT
position for one minute, then to OFF RESET position.
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