S9360B, S9361B, S9370B, S9371B, S9380B, S9381B INTEGRATED WATER HEATER CONTROLLERS
69-1792—09
16
Fig. 11. Operating sequence - S936.
CALL FOR HEAT ACTIVE
(Temperature low)
1
PREPURGE
Draft source energized
(Combustion blower or damper)
2
SPARK GENERATOR POWERED
Pilot valve opens.
3
PILOT BURNER OPERATION
OR
4
Pilot burner does not light.
After retry delay system retries.
If retries exceed maximum, timed
lockout is entered.
Pilot burner lights.
Ignition module senses flame
current and continues.
FLAME CURRENT SENSED
Spark generator off,
Main valve opens.
5
MAIN BURNER OPERATION
Ignition module monitors pilot flame
current.
6
CALL FOR HEAT INACTIVE
(Temperature at setpoint)
Valves close
7
POSTPURGE
Draft source de-energized after time.
(Combustion blower or damper)
8
POWER INTERRUPTION
System shuts off
PILOT FLAME FAILURE
Valves close, after recycle delay
system recycles. If recycles exceed
maximum, timed lockout is entered.
START
STAGE 1
PREPURGE
STAGE 2
TRIAL FOR IGNITION
STAGE 3
MAIN BURNER
OPERATION
STAGE 4
POSTPURGE
END
M24054