Do New Gas Water Heaters Require Spill Switches?

How Gas Heaters Work

• Gas water heaters heat water using natural or other types of gases. A pilot light burns continuously in the base of the heater. When the heater sensor detects that hot water is needed, the pilot light ignites the main gas jet, which heats the water inside the tank. Gas fumes generated by the combustion rise up through the heater and into a funnel placed on top of the appliance called a flue. From here, the gases make their way through duct work to the outside air.

Venting Heaters

• It's important to vent gas water heaters and other appliances properly. Otherwise, the exhaust gases can build up and present a danger. One of the chief components in exhaust gases is carbon monoxide, which can quickly be absorbed in the bloodstream and can be fatal. Venting the gases also helps to prevent the possibility of an explosion from unburned gas fumes.

Spill Switches

• The purpose of spill switches is to detect when too much exhaust gases are generated by the heater and switch the heater off. Spill switches are mounted directly next to the flue and secured in place with screws. Two wires lead from the sensor down to the control panel on the heater. Many of these spill switches also feature a reset button for restarting the heater after the switch trips. There are different types of spill switches that can detect different gases, such as natural gas or carbon monoxide.

Spill Switch Requirements

• The requirements for a spill switch vary from municipality to municipality, but in the vast majority of the United States, new water heaters require that a spill switch be installed. You can find the specific building codes for your area by consulting with city hall or the department that handles building codes in your location. Spill switches can even be installed in older hot water heaters. They're relatively cheap and not hard for the DIYer to install.