69W43 Furnace Flame Sensor

Key Features

• Sensing rod detects flame presence for furnace operation
• Angled probe design
• Overall width: 4-5/8 in
• Features a 3/16 in male terminal for connection
• Durable construction for long service life

Replaces / Cross-Reference Part Numbers

• 69W4301
• LB-74940B
• 10-6840

Compatibility & Fitment

• Direct replacement for specific furnace models from brands including:
• Armstrong
• Ducane
• Lennox
• Verify compatibility with your furnace model number prior to purchase.

When to Replace

• Furnace starts the ignition sequence but shuts off after a few seconds.
• Furnace control board indicates a flame sensor fault code.
• Visible carbon buildup, corrosion, or damage on the existing sensor rod.
• The ceramic insulator is cracked or broken.

Installation Tips

• Disconnect electrical power to the furnace unit before servicing.
• Avoid touching the metal rod with bare hands; handle by the ceramic base.
• Ensure the sensor is correctly positioned in the pilot or main burner flame.
• Confirm the mounting screw and wire are securely fastened.