Lennox 20J91 Flame Sensor – 20J9101

OEM Part Number: 20J9101
Catalog Number: 20J91
Brand: Lennox Genuine OEM
Product Type: Flame Sensor
Weight: 0.05 lb

Common Symptoms of a Faulty Flame Sensor

A dirty or failing flame sensor is one of the most common causes of furnace ignition problems. Common symptoms include:

• Furnace starts but shuts off after a few seconds.
• Burners ignite and then immediately go out.
• Furnace repeatedly attempts to light.
• Ignition lockout or flame failure fault codes.
• No heat even though the inducer motor and ignitor are operating normally.
• Intermittent heating during cold weather.
• Furnace cycles several times before finally staying on.

These problems are commonly seen throughout Alberta, including Calgary, Edmonton, Red Deer, Lethbridge, Medicine Hat, Fort McMurray, Grande Prairie, Airdrie, Sherwood Park, St. Albert, and Leduc, where furnaces often run around the clock during the winter.

Across Ontario, homeowners in Toronto, Mississauga, Brampton, Vaughan, Markham, Richmond Hill, Oakville, Burlington, Hamilton, Ottawa, Kingston, Cornwall, London, Kitchener, Oshawa, Whitby, Ajax, Pickering, Barrie, and Sudbury frequently experience flame sensor issues caused by normal wear and oxidation after years of furnace operation.