What component is required for all fuel-fired water heaters?

The component required for all fuel-fired water heaters is a fuel shutoff valve. This valve serves as a critical safety feature that allows for the immediate cessation of fuel supply to the water heater in case of an emergency or maintenance. It ensures that, in the event of a gas leak or malfunction, the flow of fuel can be quickly stopped, minimizing the risk of fire or explosion.

In fuel-fired systems, which may use natural gas, propane, or other combustible fuels, having a means to control the fuel supply is essential for safety and functionality. The fuel shutoff valve is typically located near the water heater and should be easily accessible.

In contrast, while other components like pressure relief valves and temperature gauges serve important roles in ensuring the safe operation and efficiency of water heaters, they do not address the direct safety concerns related to the fuel supply itself. Therefore, the fuel shutoff valve stands out as a mandatory component for all fuel-fired water heaters to ensure the safety of the system.