White-Rodgers 3L09-14 Limit Switch

The White-Rodgers 3L09-14 Limit Switch is a high-performance 1/2" bimetal disc thermal control designed for critical safety monitoring in gas-fired furnaces, unit heaters, and rooftop HVAC systems. This board mounted limit switch features a 3.12" insertion length, ensuring the sensing element is positioned accurately within the air stream for rapid response to thermal fluctuations. Engineered with a fixed open temperature of 250°F and a fixed close temperature of 210°F, this SPST (Single Pole Single Throw) device operates on an open on rise action to interrupt the burner circuit when temperatures exceed safe operating limits.

Built for industrial-grade reliability, the 3L09-14 incorporates an auto reset mechanism that restores circuit continuity once the system cools to 210°F, preventing unnecessary downtime while maintaining tight safety tolerances. This snap-disc limit control provides high-speed contact separation to minimize arcing and extend the service life of the switch. For contractors performing field maintenance, this part serves as a robust high limit safety solution for board-level configurations where precise calibration and a 40-degree differential are required for equipment protection.

• Precise Thermal Calibration: Fixed 250°F cutout protects heat exchangers from damage due to overheating.
• Optimized Airflow Sensing: The 3.12-inch insertion probe ensures high-accuracy detection in deep plenum or duct applications.
• Automated Recovery: Features automatic reset functionality at 210°F to eliminate the need for manual intervention after temporary thermal spikes.
• Rugged Bimetal Construction: Utilizes a 1/2" bimetal disc design for consistent, high-speed contact separation across high-cycle operations.
• Direct Board Mounting: Engineered for quick integration into furnace control board assemblies with standardized mounting holes.

• Can this switch replace a manual reset limit? No. This is an auto-reset limit designed for primary safety. Manual reset switches are typically required for flame rollout protection.
• Does insertion length matter during replacement? Yes. The 3.12" depth is critical for proper airflow engagement; using an incorrect length can lead to delayed tripping or nuisance cycling.
• Is this compatible with 24V or 120V circuits? This switch is rated for pilot duty and standard inductive/resistive loads typically found in residential and commercial HVAC control circuits.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.