DVS 30-2 DVS-36& DVS-42INTERMITTENT PILOT TROUBLESHOOTING, S8600H NORMAL OPERATING SEQUENCE

DVS-36 & DVS-42 INTERMITTENT PILOT TROUBLESHOOTING

If the pilot does not light, or the pilot flame current is not at least 1.0 uA and steady, the module will not energize the second main valve and the main burner will not light.

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.

S8600H NORMAL OPERATING SEQUENCE

START

STAGE 1

Trial for Ignition

STAGE 2

Main Burner

Operation

END

Thermostat, Wall Switch,

Remote, Etc. Calls For Heat

POWER INTERRUPTION

System shuts off. Restarts when

power is restored.

PILOT FLAME FAILURE Second main operator closes. Module starts trial for ignition.

Spark Generator Powered

First Valve (Pilot)

Operator Opens

PILOT BURNER OPERATION

Pilot burner lights.	Pilot burner does not light
Module senses flame current.
OR	MODULE	RESPONSE
	S8600H	After 90 seconds*pilot valve
		closes, spark stops.
	* Lockout timing is stamped on module.

IF FLAME CURRENT SENSED

•Spark generator off.

•Second valve operator (Main) opens.

MAIN BURNER OPERATION Module monitors pilot

flame current.

THERMOSTAT SATISIFIED Valves close.

Pilot and main burners are off.

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