Figure 4-3. Fuel Needle Adjustment.
Do not force the fuel needle. This may damage the fuel orifice and make correct
adjustment difficult or impossible.
(2) Turn the fuel needle valve counterclockwise one full turn, then continue in 1/8 turn increments. After each
increment inspect the exhaust. The fuel flow should be increased until there is no odor of unburned fuel or any smoke.
(3) In low ambient temperatures it may be necessary to increase the fuel flow to achieve smooth burner
f. Check that the beater shuts off when the temperature in the enclosure has reached the temperature set on the
thermostat. If conditions permit, check that the heater cycles under control of the room thermostat.
g. Stop the heater by moving the HEATER-OFF-FAN switch to OFF. The white indicator light will go out
immediately. If the heater is burning when the switch is moved to OFF, the burner flame will go out immediately, but the
ventilating and combustion blower motors will continue to run until all heat is purged from the burner. When the heat
exchanger has cooled, both motors will stop.
Change 2 4-7