L210-20F Furnace Primary Limit Switch -40°F to 180°F

L210-20F Furnace Primary Limit Switch -40°F to 180°F

Key Features

• High-temperature limit control with automatic reset
• Opens circuit at 210°F (99°C)
• Closes circuit at 190°F (88°C)
• Differential: 20°F
• Switch Action: Single Pole, Single Throw (SPST), normally closed
• Insertion Length: 3 inches

Replaces / Cross-Reference Part Numbers

• Rheem-Ruud: 47-25349-06
• Nortek / Nordyne: 41835, 626565

Compatibility & Fitment

• Designed for use as a primary high-limit switch in forced-air gas or electric furnaces.
• Fits specific furnace models from brands including Rheem, Ruud, and Nortek (Nordyne).
• Verify fitment by comparing the part number and temperature ratings (L210-20F) with the original switch.

When to Replace

• Furnace cycles on and off more frequently than normal (short-cycling).
• The main blower motor runs continuously after the heating cycle completes.
• The furnace fails to ignite or produce heat due to an open limit circuit.
• The switch fails a continuity test with a multimeter when at room temperature.
• Visible signs of damage, such as corrosion, burnt terminals, or a cracked casing.

Installation Tips

• Disconnect all electrical power to the furnace unit before beginning any service.
• Confirm the temperature ratings on the replacement switch match the original component exactly.
• Handle the new switch by its mounting plate to avoid damaging the sensor element.
• Ensure all wire terminal connections are clean, tight, and secure.
• After installation, run a full heating cycle to confirm the furnace and blower operate correctly.