Furnace limit switches are wired in series with which component?

Furnace limit switches are designed to prevent overheating by shutting off the burner when the temperature exceeds a safe level. They are crucial for maintaining safe operating conditions within the furnace. The correct component that limit switches are wired in series with is the gas valve.

When connected in series with the gas valve, the limit switch will interrupt the power supply to the gas valve if the temperature rises above the preset limit. This effectively stops the flow of gas to the burner, preventing the furnace from operating under dangerous conditions. This is a safety mechanism to ensure that if there is a temperature issue, the heating process is halted.

The other components listed, such as fans or heat anticipators, do not directly interact with the gas flow in the same critical way that limit switches do with the gas valve. The limit switch's primary function is to manage the burner operation, making the gas valve the appropriate answer for this question.