Intermatic 156T4042A Fireman SwitchThe Intermatic 156T4042A is a Fireman Switch designed for coordinated control of pool and spa heaters and filter pumps. This switch is rated for 10 amps and 250 volts AC at 60 Hz, and its primary function is to turn off a gas fired pool or spa heater approximately 20 minutes before the filter pump shuts off. This component is compatible with various pool and spa systems that require integrated time management for their heating and filtration processes.