543-020

Ensure your heating system operates safely and efficiently with this premium 3-inch high limit control switch. Designed as a critical safety component for forced-air gas furnaces and HVAC units, this switch monitors the internal temperature of the heat exchanger to prevent overheating. If the furnace temperature exceeds the safe threshold of 140°F, the switch automatically breaks the electrical circuit to shut down the burners, protecting your equipment from damage and ensuring home safety. Once the internal temperature drops by 30°F, the switch resets to allow for normal operation. This high limit switch is an essential replacement part for troubleshooting furnace short-cycling, blower motor issues, or thermal safety trips in residential heating systems.
Type: High Limit Control Switch
Size: 3-inch probe
Dimensions: 3 in (insertion depth)
Application: Used primarily in gas furnaces and forced-air heating systems as a primary safety limit to prevent heat exchanger damage.
Specifications: Opening Temperature: 140°F; Differential/Closing Temperature: 30°F below setpoint; Normally Closed (NC) circuit; Automatic reset functionality.