Copeland Comfort Control (White Rodgers) 3L09-20 Limit Switch

The White Rodgers 3L09-20 Limit Switch is a professional-grade 1/2" bimetal disc limit control designed for high-limit temperature protection in forced air heating systems. This board mounted limit switch features a 7.12" insertion length, ensuring the sensing element is positioned deep within the air stream for rapid thermal response and precise high-speed contact separation. Operating as a normally closed SPST switch, the 3L09-20 is engineered with an open on rise action that triggers at a fixed 240°F and utilizes an auto reset function once the temperature drops to the 210°F close point.

For contractors performing field repairs, this unit serves as the direct replacement for 86H73 and is compatible with various OEM HVAC equipment configurations. The robust phenolic housing and 1/2" snap disc design prioritize long-term performance and reliability in high-cycle furnace applications. Whether you are troubleshooting air flow issues or replacing a fatigued high limit sensor, the 3L09-20 provides the exact fixed temperature settings required to maintain system safety and ASHRAE compliance. This control handles standard pilot duty and power loads typical in residential and light commercial air handlers.

• Universal Compatibility: Serves as a reliable 86H73 cross reference and fits numerous HVAC board-mount footprints.
• Precise Calibration: Fixed 240°F open and 210°F close temperatures prevent nuisance tripping while ensuring safety.
• Extended Reach: The 7.12-inch probe length allows for accurate temperature monitoring in larger heat exchanger plenums.
• Industrial Build: Features a high-speed bimetal disc for crisp switching and minimized electrical arcing.
• Automatic Recovery: The auto reset limit switch design restores circuit continuity without manual intervention after cooling.

• Is the 3L09-20 a manual or auto reset switch? This model is an auto reset control, meaning it will automatically close the circuit once the plenum temperature falls below 210°F.
• Can I use this to replace a shorter insertion limit? You must match the 7.12" insertion length of the original part to ensure the sensor reaches the correct thermal zone; a shorter probe may cause delayed response times.
• Will this work on 24V and 120V circuits? Yes, this snap disc limit is rated for use across common heating control voltages, including 24V, 120V, and 240V AC applications.

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.