White-Rodgers 3F11-225 Switch

For veteran HVACR technicians, the White-Rodgers 3F11-225 represents a reliable, field-tested solution for high-temperature fan control applications. This 1/2" bimetal disc fan switch, also identified by manufacturer number 36T22-10860, is engineered with a set fixed temperature range of 217 to 232 degrees F and a 30-degree F differential. The SPST close on rise switch action ensures precise single-pole single-throw operation, bringing the blower online once the plenum reaches the cut-in temperature. Built with a stainless steel mounting bracket (loose ring style) and 1/4" quick-connect terminations, it facilitates rapid retrofitting and secure installation in tight cabinet spaces. This snap-action disc thermostat features an auto reset function, eliminating manual intervention after thermal cycles. Rated for 15A at 120 VAC and 10A at 240 VAC, it is a robust industrial component for forced-air heating systems, HVAC blower controls, and high-limit regulation where high-speed contact separation is essential for equipment safety and performance.

Key Benefits

• Broad Compatibility: Efficiently serves as an OEM replacement for diverse HVAC and appliance fan control requirements.
• Precision Thermal Sensing: Internal bimetal disc technology ensures consistent response times and fixed temp accuracy within a tight 217-232°F window.
• Durable Construction: Features an aluminum disc cup and stainless steel hardware to resist oxidation and thermal stress in high-heat environments.
• Streamlined Installation: Designed with 1/4" quick connect terminals and a flange mount for fast field service.

Common Questions

What is the difference between "Close on Rise" and "Open on Rise"?
In fan controls like the 3F11-225, "close on rise" means the circuit completes and the fan starts when the temperature hits the setpoint. In contrast, "open on rise" switches (limit controls) break the circuit to shut down burners if temperatures exceed safe limits.

Can I use this switch in a 240V system?
Yes. This White-Rodgers temperature switch is rated for both 120 VAC (15A) and 240 VAC (10A) applications, making it suitable for a variety of commercial HVAC tasks.

What causes a bimetal disc switch to fail prematurely?
The most common causes are excessive electrical arcing due to over-amping the contacts or physical contamination of the aluminum disc cup, which can insulate the sensor from the actual air temperature.

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.