When starting an intermittent spark ignition furnace, what might indicate a faulty component if the pilot flame lights but continues to spark after 90 seconds?

In an intermittent spark ignition furnace, the ignition board plays a crucial role in controlling the ignition sequence. When the pilot flame lights but continues to spark after 90 seconds, this behavior suggests a malfunction in the ignition board. The ignition board is responsible for monitoring the pilot flame and sending a signal to stop sparking once the flame is established. If the board fails to recognize that the pilot has successfully ignited and does not interrupt the sparking, it indicates that the ignition board is not functioning correctly.

This persistence in sparking is likely due to a fault in the ignition board's sensors or programming, which would mean it cannot properly assess the status of the pilot flame. In a well-functioning system, once the pilot flame is detected, the sparking should cease almost immediately. Thus, the prolonged sparking indicates that the ignition board, which is meant to regulate this process, is likely at fault. This emphasizes the board's critical role in ensuring safe and efficient operation within the ignition sequence of the furnace.