Start the combustion air blower and other related plant equipment.
Place the CONTROL MODE selector switch in the STACK position and verify the setpoint of both temperature
If all system limits are CLOSED, the LIMITS CLOSED light will come ON and the purge timer will begin its timed
Press the LIMITS SET pushbutton to energize the limits hold circuit.
If a momentary break In the limits circuit causes the system to shut down, the LIMITS CLOSED light will
come ON again as soon as the limits circuit is again satisfied To aid in troubleshooting, the LIMITS SET
light will go OUT and remain OUT. This indicates that the shutdown was caused by one or more of the
switches in the limits circuit rather than by a flame failure.
After the Purge timer has completed Its timed delay; purge latch relay, R1, will be energized and the PURGE
COMPLETE light will come ON The Tertiary Air Damper, If applicable, will be released to follow the burner fuel control
Verify that the burner control valve Is in the low fire position
10. Press and HOLD the PILOT pushbutton to start the pilot Ignition sequence.
a. The load relay and safety switch heater of the Honeywell RA890G flame relay will be energized.
b. The Ignition transformer and pilot solenoid valve will be energized.
11. If a satisfactory flame Is recognized by the UV detector
a. The safety switch heater will be de-energized.
b. Auxiliary Flame relays, R4 & R5, will be energized
c. The purge timer, 1TR, will be de-energized and reset.
d. Alarm Silence relay, R6, will be de-energized, and the flame alarm circuit will be reset.
e. The PILOT ON light will come ON.
12. Release the PI LOT pushbutton.
13. If a satisfactory flame is not established within the safety time of the RA890G flame relay:
a. The safety switch heater will continue to heat until it trips.
b. The pilot solenoid and Ignition transformer will be de-energized.
c. The RESET light will come ON. It will be necessary to open the access door on the front enclosure and reset the
flame relay before proceeding
It is recommended that power be shut off before opening the control panel. If the panel remains "hot"
while resetting the flame relay, exercise CAUTION to avoid contact with exposed terminals and wiring.