To ensure that the main burner cannot operate unless the door switch is closed, what must be done to the door switch?

The requirement that the main burner cannot operate unless the door switch is closed is fundamentally about safety and proper interlocking within the system. By interlocking the door switch with the burner control system, you create a mechanism that prevents the burner from igniting when the door is open. This is important because it minimizes the risk of injury or damage that could occur if the burner were to operate while maintenance or servicing is being performed.

This interlock functions as a safety feature, ensuring that operators and technicians are protected from the hazards associated with the burner’s operation during maintenance activities. Thus, the door switch serves a critical purpose in the overall safety protocol of gas appliances.

Other options may involve aspects of the door switch's function, but they do not specifically address the requirement that the burner should not operate without the door being safely closed. Manual control does not inherently promote safety, connecting to the power supply does not inherently limit burner operation based on the door's status, and maintenance, while necessary for any system, does not directly influence the operational condition tied to the door switch.