White-Rodgers 3F11-240 Fan Switch

The White-Rodgers 3F11-240 is a high-temperature bimetal disc fan switch engineered for heavy-duty HVAC applications requiring precision snap-action control. This 1/2" bimetal disc thermal switch features a fixed operating range of 229°F to 251°F, making it a critical component for high-limit fan sequencing. As a Close on Rise (SPST) control, it remains normally open until reaching the upper setpoint, at which time it completes the circuit to engage the blower or fan. With its substantial 100°F temperature differential, this automatic reset fan control prevents short-cycling by ensuring the system cools significantly before the contacts reopen. Designed for universal mounting, it includes a stainless steel loose ring mounting bracket and standard 1/4" quick connect terminations for efficient field replacement. This Therm-O-Disc 36T22-10862 style switch is rated for 15A at 120VAC, providing the rugged reliability needed in commercial and residential furnace environments.

Key Benefits

• Precision Temperature Regulation: Fixed 100°F differential ensures stable fan operation and reduces mechanical wear on high-static blowers.
• Broad Compatibility: The 36T22-10862 footprint serves as a standard replacement for various OEM fan limit controls.
• Durable Construction: Features an aluminum disc cup and stainless steel brackets to withstand prolonged exposure to high-heat furnace plenums.
• Simplified Installation: Integrated 1/4" quick-connect terminals allow for rapid wiring without specialized crimping tools.

Common Questions

What is the difference between this and a Limit Switch?
Unlike a high-limit switch that opens on rise to kill power for safety, the White-Rodgers 3F11-240 is a fan switch that closes on rise to activate the blower once the heat exchanger reaches the required temperature.

Can I use this for lower temperature applications?
No, this specific model is calibrated for a high range (up to 251°F). For lower staging temperatures, verify the required setpoints of your specific furnace or appliance before installation.

Does this switch require manual resetting after a trip?
This is an automatic reset control; it will reset itself once the temperature drops below the 100°F differential threshold.

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.