121-402

This high limit control switch is a vital safety component designed for HVAC systems, specifically furnaces and air handlers. Functioning as a temperature-sensitive fan disc, it monitors the internal heat levels of your heating equipment to ensure safe and efficient operation. By automatically opening or closing the electrical circuit based on precise temperature thresholds—opening at 105°F and closing at 165°F—it prevents the system from overheating and protects internal components from thermal damage. This replacement part is essential for maintaining the reliability of your residential or commercial heating system, ensuring that the blower fan and heating elements operate within specific safety parameters. If your furnace is short-cycling or the fan is not engaging correctly, a faulty high limit thermostat may be the cause.
Type: Fan Disc High Limit Control Switch
Size: Small
Dimensions: not specified × not specified × not specified
Application: Commonly used in gas furnaces, electric air handlers, and HVAC units to regulate fan operation and provide thermal safety protection.
Specifications: Temperature Range: 105°F Open / 165°F Close; Switch Logic: Temperature-actuated disc; Application: Safety Limit/Fan Control.