The White-Rodgers 3L09-3 Limit Switch is a high-performance board mount limit control designed for precise thermal regulation in HVAC furnace systems. Utilizing a 1/2" bimetal disc, this Therm-O-Disc Style 612701 features a snap-action mechanism that ensures high-speed contact separation, minimizing arcing and extending the life of the internal components. This specific Type 36T model is calibrated to open at 140F on temperature rise and automatically close at 110F, providing a 30-degree differential essential for maintaining safe operating parameters in gas-fired or electric heating equipment. Engineered for versatility, the 3L09-3 features a 3.12-inch board mount extension, allowing the bimetal sensor to reach deeper into the airstream for accurate temperature detection. This SPST (Single Pole Single Throw) switch is a direct OEM replacement limit switch for several competitive models, offering a resistive load rating of 15.0A at 120VAC and 13.0A at 240VAC. Whether you are performing a furnace limit switch replacement or a routine maintenance check, this auto-reset snap disc provides the reliable, fixed-temperature protection required by modern heating controls. Key Benefits Precise Thermal Control: Features a fixed 140F open and 110F close setpoint for consistent safety cycling. Robust Electrical Ratings: Supports a Locked Rotor Amperage (LRA) of up to 34.8A at 120VAC, making it suitable for demanding motor leads. Durable Construction: The 36T Therm-O-Disc series is recognized for its high-speed snap-action bimetal, ensuring reliable switching under varying HVACR loads. Ease of Installation: The 3.12" board mount design facilitates secure positioning on control boards or within air plenums where extended reach is critical. Common Questions Is the White-Rodgers 3L09-3 an automatic or manual reset switch? This model is an automatic reset limit control, meaning the contacts will re-close once the temperature drops to the 110F reset point. What are the terminal specifications for this board mount limit? The unit typically utilizes 1/4" quick-connect blade terminals, standard for 36T series bimetal controls, facilitating fast wiring in furnace compartments. How do I confirm compatibility with my existing HVAC system? Ensure your current part matches the 140-degree opening temperature and the 3.12" mounting length to maintain the safety sequence of your equipment. 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.
