In oil burner circuits, how must the high limit control be configured?

The high limit control is a crucial safety device in oil burner circuits, designed to prevent overheating by shutting down the burner if the temperature exceeds a predetermined level. Configuring this control correctly is essential for safe operation.

The correct configuration involves using line voltage, meaning that the control operates at the same voltage level as the main power supply for the burner. This allows the high limit control to effectively interrupt the power to the burner, ensuring that it can shut down the burner when necessary. Additionally, wiring it in series is the design requirement, as this configuration allows the control to break the circuit when it trips, stopping the burner from operating anytime it exceeds the high limit temperature.

Using line voltage ensures that the high limit control has a sufficient power level to operate effectively, while the series wiring means that any interruption caused by the control will directly impact the burner operation, providing the necessary safety intervention.