Which type of ignition system remains on while the burner is running?

The correct answer is based on the operation of various ignition systems used in oil heating applications. Continuous ignition systems operate in a manner where the ignition source remains active for the entire duration the burner is running. This uninterrupted flame source ensures that if there are any fluctuations in the combustion process, the burner can maintain ignition without needing to relight.

In contrast, intermittent ignition systems, which involve a cycle of igniting and extinguishing, would not remain continuously on; rather, they activate only at certain points, usually during the startup phase of the burner cycle. Similarly, choices like interrupted duty and random ignition systems do not provide continuous ignition during operation, but rather are designed for selective or unscheduled ignition based on specific conditions. This distinction makes continuous ignition the most reliable choice for maintaining consistent operation and flame stability in a burner system.