In a conventional furnace, the high limit switch is wired in series with which component?

In a conventional furnace, the high limit switch is specifically designed to prevent overheating by shutting off the gas supply if the temperature exceeds a safe limit. This switch is wired in series with the gas valve. When the high limit switch is activated due to high temperature, it interrupts the electrical circuit to the gas valve, thereby preventing the flow of gas to the burner. This safety feature is crucial for protecting the furnace components and ensuring safe operation.

The blower motor, thermostat, and fuel pump play different roles in the furnace operation. The blower motor primarily circulates air through the system, and while it may interact with the furnace controls, it is not responsible for cutting off the gas. The thermostat regulates the temperature of the environment but does not directly control the gas supply in relation to high limitations. The fuel pump, if used in certain heating systems, delivers fuel but does not interact with the high limit switch in the same manner that the gas valve does. Thus, the high limit switch's connection in series with the gas valve is essential for safety and operational control in a conventional furnace.