When the ‘’'Operating Limit Control ‘’'setting is reached to open the circuit or if the burner switch is turned “off,” the following sequence occurs:
- The fuel valve is de-energized and the flame is extinguished.
- The timer begins operation and the blower motor continues running to force air through the furnace in the post-purge period.
- At the end of the programmed post-purge period, the blower motor is turned off.
- The air pump motor of an oil-fired burner is also turned off.
- The timer has returned to its original starting position and stops.
- The unit is ready to restart.