52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack
Two 52W29 furnace flame sensor replacement rods with white ceramic insulators and metal mounting brackets.
52W29 furnace flame sensor showing product dimensions of 4.1 inches and 5.4 inches.
52W29 furnace flame sensor close-up with text overlay highlighting sensitive flame detection and safety features.
Diagram of 52W29 furnace flame sensor components including sensor head, ceramic casing, mounting bracket, and metal rod.
Close-up of a single 52W29 furnace flame sensor with mounting bracket and electrical terminal.
Compatibility chart for 52W29 furnace flame sensor listing compatible furnace models.
Technician installing a 52W29 furnace flame sensor to fix heating system issues like short cycling.
Installation guide showing steps to replace a 52W29 furnace flame sensor.
Single 52W29 furnace flame sensor replacement part with mounting bracket and electrical terminal.
Two 52W29 furnace flame sensor replacement rods with white ceramic insulators and metal mounting brackets.
52W29 furnace flame sensor showing product dimensions of 4.1 inches and 5.4 inches.
52W29 furnace flame sensor close-up with text overlay highlighting sensitive flame detection and safety features.
Diagram of 52W29 furnace flame sensor components including sensor head, ceramic casing, mounting bracket, and metal rod.
Close-up of a single 52W29 furnace flame sensor with mounting bracket and electrical terminal.
Compatibility chart for 52W29 furnace flame sensor listing compatible furnace models.
Technician installing a 52W29 furnace flame sensor to fix heating system issues like short cycling.
Installation guide showing steps to replace a 52W29 furnace flame sensor.
Single 52W29 furnace flame sensor replacement part with mounting bracket and electrical terminal.

52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack

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CONFIRM THIS PART FITS
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52W29 Furnace Flame Sensor

Key Features

  • Constructed with a metal alloy rod and a ceramic insulator for high-temperature durability and conductivity.
  • Detects burner flame to allow safe and continuous furnace operation.
  • Rod Length: 2-3/4 inches
  • Connector Size: 3/16 inch

Replaces / Cross-Reference Part Numbers

  • 52W29
  • 52W2901
  • 31L71
  • 31L7101
  • LB-74940A
  • 28PV41
  • 903600
  • FLS52W29

Compatibility & Fitment

  • Direct replacement for specific furnace models from Lennox, Armstrong, and Ducane.
  • Confirmed fit for G40, G41, G50, and G51 series furnaces.
  • Verify fitment by matching your original part number to the cross-reference list.

When to Replace

  • The furnace cycles on but the burner shuts off after a few seconds.
  • The furnace fails to produce heat or does not stay lit.
  • The ceramic insulator on the existing sensor is cracked or broken.
  • The metal rod is corroded, covered in carbon buildup, or physically damaged.

Installation Tips

  • Disconnect all electrical power to the furnace before beginning service.
  • Handle the new sensor by its ceramic base; avoid touching the metal rod with bare hands as skin oils can cause premature failure.
  • Ensure the single mounting screw is secure but not overtightened to avoid cracking the ceramic.
  • Position the sensor so the metal rod is properly enveloped by the burner flame during operation.
52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 1
52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 2
52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 3
52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 4
  • 52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 1

    WIDE COMPATIBILITY

    Compatible with many models of Lennox, Ducane and Armstrong Furnaces
  • 52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 2

    DURABLE MATERIAL

    This part is made of high-quality metal material with ceramic porcelain for superior conductivity and high reliability.
  • 52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 3

    SAVING SOLUTION

    Enjoy the great feeling when your furnace is repaired and works properly like before, BlueStars brings DIY solutions to help you deal with any trouble
  • 52W29 Furnace Flame Sensor Replacement - For Lennox Armstrong & Ducane Furnaces - 2 Pack 4

    IMPORTANT NOTE

    This is a replacement part designed to be compatible with certain appliances. Any brand names mentioned are used solely to indicate compatibility.
CONNECTING LIVES, ENERGIZING MOMENTS

CONNECTING LIVES, ENERGIZING MOMENTS

Compatible Models

Locate the model number of your appliance or equipment on the manufacturer's label and use it to check compatibility before ordering

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FAQs

This flame sensor is used on certain Lennox, Armstrong, and Ducane furnaces. Reported compatible series include G40, G41, G50, G51, G60, G61, and G71. Because furnace revisions can vary, match your original part number and furnace model before ordering.
Known part numbers associated with this flame sensor include 52W29, LB-74940A, 52W2901, 31L71, 31L7101, and 28PV41. Matching the number on your original sensor or parts list is the best way to confirm fit.
The flame sensor verifies that the burner flame is actually present during ignition and heating operation. If the sensor does not detect flame, the control board shuts off gas to prevent raw gas from continuing to flow.
Common signs include the furnace igniting and then shutting back off within a few seconds, short cycling, repeated ignition attempts, or no sustained heat even though the burners briefly light. A contaminated or failing flame sensor is a common cause of 'lights then shuts off' behavior.
Usually no. On many furnaces, replacement is a straightforward service job that takes about 10 to 20 minutes. Typical tools are a screwdriver or nut driver to remove the access panel and sensor mounting screw. Always shut off electrical power to the furnace before servicing.
If the sensor is only coated with oxidation or combustion residue, gentle cleaning can sometimes restore operation temporarily. If the furnace problem returns, the sensor is cracked, the rod is heavily worn, or the porcelain insulator is damaged, replacement is usually the better fix.
Inspect the sensor wire and terminal connection, verify the burner flame is strong and stable, and check for burner contamination or grounding issues. A weak flame, poor furnace ground, or ignition problem can mimic a bad flame sensor, so confirming those basics can help avoid repeat shutdowns.