THERMAL SWITCH No one knows the furnace business better than Lennox Our new THERMAL SWITCH furnace control adds functionality and value while delivering a smart home capable of anticipating and adjusting to meet the needs of you and your family, regardless of how hot it gets outside or how cold it gets inside Lennox 75W43 THERMAL SWITCH controls attached to furnaces, boilers, and radiant heaters Use a thermal switch to trigger electrical switches, motors, or valves when temperature rises above a predetermined level THERMAL SWITCH also controls the circulation of liquid through pipes or tanks The Lennox THERMAL SWITCH for gas furnace and air-conditioner, 90% efficient up to 400 amps Thermal switch Thermostat controls your heating/cooling system when the temperature drops or rises outside of set limits These thermal switches are designed to be installed in a dummy load (air handler) They have a glass bulb diffuser and draw 1/2 Amp each The terminals are marked for polarity The Lennox 75W43 thermal switch features 2 copper terminals for wiring This thermal switch is used to control a variety of air conditioner and heat pump systems It is guaranteed to fit in your Lennox product, or you get your money back These three-way thermal switches are used for automatic temperature control of heating and cooling systems, such as furnaces, boiler fireplaces, air conditioners, and many more The Lennox 75W43 is designed for use with your system's current furnace, this thermal switch features two 90 amp fuses and an operating range of 35 to 110 degrees Fahrenheit