Supco SHL504 Gas Furnace Limit Switch L240-40F

The Supco SHL504 is a high-quality gas furnace limit thermostat designed to provide reliable temperature control and safety protection for residential and light commercial HVAC systems. This L240-40F limit switch features proven bimetal disc technology that automatically opens on temperature rise and closes when cooled to maintain safe operating conditions.

Key Features:

• L240-40F SPST (Single Pole Single Throw) configuration
• Opens at 240°F, closes at 200°F (40°F differential)
• Snap-action bimetal disc design for quick, reliable switching
• Compact 1/2-inch mounting design for versatile installation
• CSA approved and UL recognized for safety compliance
• 36T electrical rating suitable for 25 amps at 240VAC
• Automatic reset functionality

This limit switch serves as a direct OEM replacement for Bryant P331-2217, Carrier HH12ZA252Z, and Bryant HH12ZA240. The SHL series offers economical, reliable performance in plenum thermostat applications, protecting gas furnaces from overheating by interrupting power when unsafe temperatures are detected. The automatic reset feature allows the system to resume normal operation once temperatures return to safe levels.