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4. Turn gas control switch to OFF or turn knob clockwise to OFF.
5. Wait 5 minutes to clear out any gas and then smell for gas (including near floor).
a. If you smell gas, STOP! and follow steps in DANGER message listed above or on heater operating label.
b. If you do not smell gas, proceed to step 6.
6. Turn gas control switch to ON or turn knob counterclockwise to ON.
7. Close access door.
8. Turn ON electric power to heater.
9. Set thermostat to desired setting.
a. If heater does not operate, follow instructions in step 13 or on heater operating label and call your service
technician.
b. If heater operates, thermostat calls for heat, which energizes venter motor.
10. Pressure switch closes, which fires unit.
11. Burner flame is sensed and in 30 seconds after combination gas valve is energized, fan motor is energized.
12. If flame is extinguished during main burner operation, integrated control system closes main valve and must be
reset by interrupting power to control circuit (refer to lighting instructions provided with heater).
13. TO TURN OFF GAS TO APPLIANCE:
a. Set thermostat to lowest setting.
b. If service is to be performed, turn off all electric power to appliance.
c. Open the access door.
d. Turn gas control switch to OFF or turn knob clockwise to OFF (do not force).
e. Close access door.
Operating Sequences
Table 20 describes the heater’s normal operating sequence. Table 21 describes the heater’s abnormal heat cycle
functions. Table 22 describes the heater’s fault modes. Refer to Table 28 for LED indications.
Table 20. Operating Sequence (Normal Heat Cycle)
Step Condition Action
1. Call for
heat
Terminal W is energized Thermostat calls for heat by energizing terminal W
Control determines whether limit switch is open or closed and if pressure switch is open
Limit switch is open Control deenergizes gas valve, turns fan/blower motor onto heat speed, and runs venter motor
SSD displays “5”
Control is in soft lockout “L” before returning to normal operation
Pressure switch is closed SSD displays “4”
Control waits indefinitely for pressure switch to open
Pressure switch is open Control proceeds to step 2
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