This part is for propane water heaters only. It will only work on propane heaters. The electronic gas control valve incorporates an LED status indicator that monitors system operation and service diagnostics. PROPANE Gas control located within hot water heater uses a thermopile to generate the power needed to operate the electronic gas control without requiring an external power source. This product has been certified by a third party to be compliant with the “Safe Drinking Water Act” requirements for low lead in potable (human consumption - drinking and cooking) and non-potable water applications (non-human consumption). Thermostat is compatible with all A.O. Smith branded heaters including A.O. Smith, State Water Heaters, American Water Heater, and Reliance. Please be aware part may come labeled RESIDEO as there was a corporate acquisition. It is still the correct Honeywell part!