White-Rodgers 3L11-170 Limit Switch

For technicians servicing high-limit safety circuits, the White-Rodgers 3L11-170 stands as an industry-standard HVAC limit switch designed for precision and rapid thermal response. This 1/2 inch bimetal disc control features a fixed setpoint of 165 to 175 degrees F, making it a critical component for protecting furnace heat exchangers from over-temperature conditions. Built on the proven 36T21-10852 chassis, this SPST (Single Pole Single Throw) configuration utilizes an Open on Rise switch action to break the circuit when thermal limits are exceeded, ensuring immediate system shutdown for safety.

The 3L11-170 is engineered with a 30 degree F differential, allowing for a reliable cooling period before the auto reset mechanism re-engages the circuit. Its low-profile design, featuring 1/4 inch quick-connect terminals and a surface mount bracket, allows for versatile installation in tight plenums or ductwork. Whether you are performing a furnace limit switch replacement or troubleshooting a snap disc thermostat on a residential blower assembly, this component provides the electrical ratings (up to 15A at 120VAC) required for rugged, long-term performance in demanding HVACR environments.

• Universal Compatibility: The standard 1/2" disc footprint and 36x series design replace a wide range of OEM limit controls.
• High-Speed Contact Separation: The snap-action bimetal disc ensures high contact pressure and rapid break, reducing arcing and extending component life.
• Simplified Installation: Equipped with a loose ring stainless steel bracket for easy alignment and standard 1/4" spade terminations for fast wiring.
• Reliable Safety: The fixed temperature setting prevents field tampering, maintaining the original safety parameters of the equipment.

• What does "Open on Rise" mean for this part? This means the switch is normally closed (NC) at room temperature. Once the internal sensor reaches the 165-175°F threshold, the contacts snap open to break the electrical path.
• Can this be used for fan control? No. This is a limit switch. For fan operation (close on rise), you would typically require a White-Rodgers "3F" series control.
• How do I verify if the switch has tripped? Use a multimeter to check for continuity across the terminals. If the equipment is cool and you have an open circuit (OL/no beep), the switch has failed or is stuck open.

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.