Which type of ignition system turns off after the flame is established?

The type of ignition system that turns off after the flame is established is an interrupted duty ignition system. This approach is designed to provide a spark or ignition source only during the initial startup phase of the burner. Once the flame is successfully ignited and confirmed by the flame detection system, the ignition source is turned off.

This method is efficient because it conserves energy by not maintaining an active spark during normal operation when the flame is already present. Interruption after ignition minimizes wear on the igniter and reduces the risk of overheating. This design is particularly important in applications like oil heating systems where continuous ignition is unnecessary and could lead to increased maintenance needs or decreased reliability.

In contrast, continuous duty systems maintain a constant ignition source, which is not as efficient and may lead to higher energy consumption and increased component wear. Intermittent ignition systems are similar but re-initiate the ignition if the flame goes out, rather than just turning off the spark after ignition. Manual ignition relies on user intervention to ignite the burner, which does not fit the automatic operation criteria implied by the question.