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SparkGenerator Powered
FirstValve (Pilot)
OperatorOpens
Pilotburner lights.
Modulesenses flame current.
PILOT BURNER OPERATION
MODULE
S8600H
*Lockout timing is stamped on module.
RESPONSE
After90 seconds*pilot valve
closes,spark stops.
OR
IFFLAME CURRENT SENSED
Sparkgenerator off
Secondvalve operator
(Main)opens.
MAINBURNER OPERATION
Modulemonitors pilot
flamecurrent.
THERMOSTATSATISFIED
Valvesclose. Pilot and
mainburners are off.
START
STAGE1
Trialfor Ignition
STAGE2
MainBurner
Operation
END
S8600H NORMAL OPERATING SEQUENCE
Pilotburner does not light
Thermostat,Wall Switch,
Remote,Etc. Calls for Heat
POWERINTERRUPTION
Systemshuts off. Restarts when
poweris restored.
PILOTFLAME FAILURE
Secondmain operator closes.
Modulestarts trial for ignition.
Safety Lockout
S8600H provides 100 percent shutoff, or safety lockout. A timer
starts timing the moment the trial for ignition starts. Ignition spark
continues only until the timed trial for ignition period ends. Then
the module goes into safety lockout. Lockout de-energizes the first
main valve operator and closes the first main valve in the gas control,
stopping pilot gas flow. The control system must be reset by setting
the thermostat below room temperature for one minute or by turning
off power to the module for one minute.
Main Burner Operation
When the pilot flame is established, a flame rectification circuit is
completed between the sensor and burner ground. The flame sensing
circuit in the module detects the flame current, shuts off the spark
generator and energizes the second main valve operator. The
second main valve opens and gas flows to the main burner, where
it is ignited by the pilot burner. The flame current also holds the
safety lockout timer in the reset (normal) operating condition.
When the call for heat ends, both main valve operators are de-
energized, and both main valves in the gas control close.
CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper
and dangerous operation. Verify proper operation after
servicing.
INTERMITTENT PILOT TROUBLESHOOTING