Abstract: A fire extinguishing system for suppressing fires on cook stoves, fryers or other heating or heated devices with fire suppressant dispensed through nozzles is powered by batteries which provide current for both a detection circuit including a pair of heat sensors and control circuitry and current for a gas or electric house current shut-off. The appliance shut-off device is operated by the standard hardwired interconnect cable that provides a signal between the control board and shutoff device or by an optional sonic receiver assembly that is acoustically tuned to detect an audible alarm emitted by a signal from the main control board. Preferably, the heat sensors are diodes, but in alternative embodiments may be thermistors or active temperature sensors. Mounting of heat sensors and nozzles are facilitated by tees and 90 degree elbows.