TM9-4120-400-14
2-6. OPERATIONAL CHECKS. - continued
c. Using the operating levers, adjust the louvers in both sections of the return air louver assembly to the fully
open position.
d. Turn the fresh air damper control to the fully closed (up) position.
e. Check that the unit is connected to the proper power source and that power has been connected to the
unit for four hours.
Figure 2-5. Power Connectors
f. Check to see that the CONTROL CIRCUIT BREAKER and the COMPR CIRCUIT BKR are in the ON position.
Figure 2-6. Control Panel
g. Turn the MODE SELECTOR switch to VENT (ventilate). The evaporator fan should start immediately. Use
a paper streamer or other method to check the airflow into the return air louver and out of the conditioned air
supply louver. Check the EVAPORATOR FAN SPEED switch at both the HIGH and the LOW speed settings.
There should be noticeably more airflow at the HIGH speed setting.
h. To check maximum ventilation with fresh air, first turn the fresh air damper control wheel to fully open (down)
then adjust the louvers in both sections of the return air louver fully closed. Check the fresh air inlet located on the
lower left corner of the back of the unit using a paper streamer or other method to be sure that air is being drawn in.
2-8
