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Fuel Valve Solenoid
The fuel solenoid valve needs to be removed to perform this test. 12 volts applied to the fuel
solenoid valve activates an electromagnet that pulls the valve open. With no power applied, a
spring pushes the valve closed. Blow through the valve to verify proper operation. Replace
valve if not functioning properly.
Fenwal Ignition Control
The Fenwal Ignition Control creates sparks at the electrodes for igniting the pilot light, and
supplies power to the fuel valve at the appropriate times. The controller receives voltage from
either the thermostat or main power switch (depending on the system) to begin operation. A
flame sensing circuit is incorporated for control of the fuel valve if the flame goes out.
When the power switch is turned on, or when the thermostat calls for heat, a 12 volt signal is
sent to the controller. The controller will then create sparks at the electrodes. At the same
time, the controller also sends a 12 volt signal to the fuel valve causing it to open. This allows
fuel into the pilot light and it is ignited by the sparks at the electrodes.
The flame sensing circuit will signal the controller that ignition was successful. The controller
will then shut off the sparks. The fuel valve will remain open to keep the flame burning.
If the controller does not sense a flame within approximately six to seven seconds, it will shut
off the fuel supply and the sparks. The controller will then "lock out".
If the flame should go out for any reason, the controller will try for re-ignition, if re-ignition is
not successful in six to seven seconds, the controller will "lock out".
If a lock out situation occurs, the main power switch must be shut off, then on again to reset
the system. (continued on next page)
FUEL SOLENOID VALVE
IGNITION CONTROLLER
HIGH VOLTAGE LEAD
IGNITOR AND FLAME
SENSOR
TROUBLE SHOOTING LP Burner
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