INTERMITTENT PILOT TROUBLESHOOTING
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
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.
S8600H NORMAL OPERATING SEQUENCE
START
STAGE 1 Trial for Ignition
Thermostat, Wall Switch, Remote, Etc. Calls for Heat
Spark Generator Powered
First Valve (Pilot)
Operator Opens
POWER INTERRUPTION
System shuts off. Restarts when
power is restored.
PILOT FLAME FAILURE
Second main operator closes. Module starts trial for ignition.
STAGE 2
Main Burner
Operation
END
PILOT BURNER OPERATION
Pilot burner lights. Pilot burner does not light
Module senses flame current.
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| S8600H | After 90 seconds*pilot valve | ||
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| closes, spark stops. |
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| * Lockout timing is stamped on module. | |||
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| IF FLAME CURRENT SENSED |
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| Spark generator off |
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| Second valve operator |
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| (Main) opens. |
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| MAIN BURNER OPERATION |
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| Module monitors pilot |
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| flame current. |
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| THERMOSTAT SATISFIED |
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| Valves close. Pilot and |
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| main burners are off. |
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Page 37 |
