White-Rodgers 3F11-120 Fan Switch

The White-Rodgers 3F11-120 is a heavy-duty 1/2" bimetal disc fan switch designed for precision temperature control in furnace and air handler applications. This Therm-O-Disc style 10847 (Type 36T22) operates on a close on rise logic, making it a reliable choice for cycling blowers or fans once the plenum reaches the setpoint. It features a factory-calibrated range of 113 to 127 degrees Fahrenheit (45 to 53 Celsius) with a fixed 30 degree Fahrenheit differential. This ensures consistent thermal response and prevents rapid cycling of the motor. Rated for use in both 120V and 240V circuits, this SPST thermostat switch is a standard HVAC replacement part for contractors servicing older units that require a flanged, surface-mount bimetal interface. Its compact 36T series construction allows for rapid heat transfer and accurate sensing in high-limit or fan control configurations, ensuring the fan limit control functions according to OEM specifications.

Key Technical Benefits:

• Broad Compatibility: Replaces Therm-O-Disc type 36T22 and style 10847 components commonly found in residential HVAC equipment.
• Precision Calibration: Close on rise action at 115-125°F provides reliable fan activation to prevent heat exchanger overheating.
• Durable Construction: The 1/2" bimetal disc design is engineered for high-cycle snap-action performance in demanding thermal environments.
• Easy Installation: Features a standard mounting flange for secure attachment to the furnace heat exchanger or plenum wall.

Common Contractor Questions:

What is the differential for the White-Rodgers 3F11-120?
This switch has a fixed 30°F differential, meaning if it closes at 120°F to start the fan, it will open at approximately 90°F to stop the fan.

Is this a limit switch or a fan switch?
Because this is close on rise, it functions as a fan switch to turn a blower on when it gets hot. A limit switch typically opens on rise to break the burner circuit.

Can I use this 36T22 in 240V applications?
Yes, the White-Rodgers 3F11-120 is rated for various voltages, including 120VAC and 240VAC, provided the inductive load does not exceed the amperage rating on the disc housing.

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.