Supco SHL508 Plenum Limit Switch L190-20F

The Supco SHL508 SPST Plenum Limit Switch is an electrical control component used to regulate air temperature within duct sections. It open at 190F and closes at 170F to regulate equipment operation in HVAC systems. The switch is installed in forced-air heating and cooling systems where it signals control circuits in furnaces, air handlers, or heat pumps. By responding to excessive temperature rise, it supports managing system cycling and protects internal components. It operates as part of the safety and control logic within residential and commercial connections in duct systems.