11-1/2" Insertion Fan and Limit Controller with 125 F fan on/100 F fan off, 200 F high limit

The Honeywell L4064B2210 Fan and Limit Controller provides precise temperature regulation and dependable protection for warm air furnace systems.

The Honeywell L4064B2210 combines both fan and limit control functions in one durable, easy-to-install device. Featuring an extra-long 11-1/2-inch insertion element, it provides accurate temperature sensing in large furnace plenums to ensure reliable blower operation and overheating protection. Engineered for performance and longevity, this controller maintains safe, efficient operation of forced warm air heating systems.

• Model number L4064B2210 identifies the Honeywell Fan and Limit Controller featuring an 11-1/2-inch sensing element for extended reach and enhanced accuracy.
• Designed for warm air furnaces to regulate blower operation and provide high-limit temperature protection.
• Combines fan control and limit safety shutoff in one compact, reliable assembly.

Technical Data & Performance

• Product Type: Fan and Limit Controller.
• Brand: Honeywell.
• Element Length: 11-1/2 inches – ideal for large furnaces or duct systems requiring deep temperature sensing.
• Fan Control Range: Adjustable; typically Fan ON: 125°F (52°C) / Fan OFF: 100°F (38°C).
• High Limit Range: Adjustable up to 200°F (93°C) – protects furnace from overheating by shutting off the burner when the limit temperature is exceeded.
• Switch Type: SPST fan control / SPST limit switch combination for dual functionality.
• Electrical Rating: 8A @ 120V AC (resistive load); suitable for blower motor and burner circuit control.
• Application: Controls blower fan operation and provides high-temperature safety shutoff in warm air furnaces.
• Sensing Element: Bimetallic coil sensor for accurate temperature response and stable operation.
• Differential: Adjustable fan differential for optimized blower cycling and comfort.
• Construction: Metal sensing element with durable housing and temperature calibration dial.
• Mounting Type: Surface-mounted with insertion probe extending into the furnace plenum.
• Reset Type: Manual reset high limit for additional safety.
• Voltage Rating: 120V AC nominal.
• Ambient Operating Range: -40°F to 190°F (-40°C to 88°C).
• Temperature Range: Sensing up to 250°F (121°C) maximum.
• Function: Turns blower ON at set temperature, OFF when cooled, and limits burner operation if temperature exceeds safe threshold.
• Safety Protection: Internal safety limit switch prevents furnace overheating and damage to the heat exchanger.
• Installation: Standard OEM or retrofit installation; adjustable mounting plate for quick alignment.
• Termination Type: Screw terminals for secure electrical connections.
• Maintenance: Minimal maintenance required; check temperature settings during annual furnace service.
• Compliance: Meets UL, CSA, and ANSI standards for furnace safety controls.
• Packaging: Supplied as a complete control assembly with calibration instructions.
• Warranty: Protected by Honeywell’s Limited Manufacturer’s Warranty ensuring product reliability and safety.