White-Rodgers 3L05-3 Limit Switch

The White-Rodgers 3L05-3 Limit Switch is a professional-grade snap disc limit control engineered for high-limit protection in residential and commercial heating systems. This adjustable snap disc thermostat features a temperature range of 210°F to 250°F, allowing technicians to fine-tune the cut-out point for specific furnace or appliance requirements. With an SPST open on rise switch action, it provides a critical safety break in the electrical circuit when the sensed temperature exceeds the user-defined threshold. The 40 degree F differential ensures the system sufficiently cools to approximately 170°F-210°F before the auto reset limit switch automatically re-engages the circuit.

Built as a versatile HVAC high limit replacement, the 3L05-3 (Therm-O-Disc style 74T11-310712) simplifies truck stock by replacing multiple fixed-temperature discs. It is designed for flanged airstream mount applications and features standard 1/4-inch quick connect terminals for rapid field installation. Rated for 14.0A at 120VAC and 125VA pilot duty, this 3L05-3 adjustable limit offers the rugged reliability expected in high-heat environments. Whether you are servicing a gas furnace or industrial heating equipment, this control provides the precise thermal regulation required for safe operation.

Key Benefits for Contractors

• Broad Replacement Versatility: The 3L05 series is engineered to replace a wide range of fixed-temperature snap discs, significantly reducing the necessity for large localized inventories.
• Field Adjustability: Features an integrated dial to set the high limit cut-out between 210°F and 250°F, ensuring exact matches for OEM specifications.
• Automatic Reset Logic: The snap disc auto reset eliminates the need for manual intervention once temperatures return to safe operating levels.
• High Inductive Capacity: Rated for up to 14A full load at 120V, making it suitable for both control circuits and direct motor loads.

Common Technical Questions

What is the difference between open on rise and close on rise?
The 3L05-3 is an open on rise control, meaning it breaks the electrical connection when the temperature hits the high limit to prevent overheating. Close on rise models are typically used for fan control to start a blower when the heat exchanger warms up.

How do I install the flanged airstream mount?
This control is designed for surface mounting where the sensing disc is exposed to the airstream. Ensure the mounting surface is clean and the disc has direct contact with the heated air or surface for accurate thermal response.

Can this replace a fixed 240°F limit switch?
Yes, because this is an adjustable limit switch, you can set the dial to 240°F to match the original equipment manufacturer's safety setpoint.

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.