Gas cutoff system
Posted by keepersg , 22 November 2020 · 515 views
We've had repeated problem with pans being left on the burners in our kitchen and the house filling with smoke before anyone realizes what's happening. In order to prevent this from happening again, I constructed a timed gas cutoff system that is mounted inside the cabinet on which the cooktop is mounted. The gas piping routes the gas supply for the cooktop through an electrically controlled valve. There is a manual bypass valve which is the yellow valve in the photo, Initially, I tried a 120VAC solenoid valve but the hum from the valve proved unacceptable. I substituted a low voltage ball valve powered by a spare doorbell transformer which is normally closed (it's a valve, not a circuit) and opens when powered. When power is removed it returns automatically to closed. Motion sensors in the the kitchen determine if anyone is present (through an Elk M1G) and programs on an ISY994i monitor this. When motion is detected the valve is opened. If there's no motion for 10 minutes, the valve closes. In constructing the piping it is critical to pressure test the fittings to make certain there are no leaks. A second test with soap solution after installation offers further assurance. A gas detector in the kitchen will also turn the gas off as will a smoke detector in the adjacent dining room.