White-Rodgers 3L11-175 Limit Switch

The White-Rodgers 3L11-175 Limit Switch is a mission-critical 1/2" bimetal disc limit switch designed for precision temperature regulation in high-demand furnace and HVAC applications. Engineered for reliability, this fixed temperature switch features a factory-set open on rise operation, calibrated to interrupt the circuit between 170°F and 180°F. This specific 36T21-10854 model utilizes a snap-action bimetal disc to ensure high-speed contact separation, providing consistent SPST (Single Pole Single Throw) switching under heavy inductive loads. The integrated automatic reset capability with a 15°F differential ensures that once the system cools to safe operating levels, the circuit re-engages without manual intervention.

For field installations, the 3L11-175 includes 1/4" quick-connect terminals and a loose-ring stainless steel mounting bracket for versatile positioning. This HVAC high limit control is cross-compatible with various Emerson and Therm-O-Disc 36T series configurations, making it a standard replacement for residential gas furnaces, unit heaters, and commercial blowers where over-temperature protection is required.

• Snap-Action Reliability: Quick-break contact mechanism reduces arcing and extends component life in high-voltage circuits.
• Precise Calibration: Fixed 170-180°F cutout range provides accurate thermal protection for heat exchangers and blower motors.
• Simplified Installation: Standard 1/2" disc footprint and loose-ring bracket facilitate rapid swap-outs in tight furnace compartments.
• Automatic Reset: Recovers system operation automatically after a 15-degree temperature drop, minimizing contractor callbacks.
• Universal Compatibility: Replaces common White-Rodgers limit controls and cross-references to standard 36T21 series bimetal thermostats.

• How can I verify the switch action on this part? The "L" in 3L11 indicates a "Limit" control, which is functionally open on rise to break the circuit when a temperature ceiling is reached.
• What are the electrical ratings for the 3L11-175? These units are typically rated for 15A at 120VAC and 10A at 240VAC, making them suitable for most residential blower and heating control circuits.
• Can this be used as a fan control? No, fan controls typically require "close on rise" (identified by the "F" prefix) to activate a blower as the plenum heats up; the 3L11 is strictly a safety high-limit switch.

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.