Lennox 52W29 Flame Sensor Kit LB-74940A

The Lennox 52W29 Flame Sensor Kit LB-74940A is a Lennox flame sensor for HVAC repair and replacement work. Use it when the part number 52W29 and the listed specifications match the equipment being serviced.

Lennox 52W29 Flame Sensor Kit (LB-74940A) is an OEM flame sensing kit used on selected Lennox gas furnaces to monitor burner flame presence and allow the control board to safely prove flame during operation. Key Features: OEM Lennox flame sensor kit, part number 52W29 (LB-74940A) Designed to detect burner flame and signal the furnace control board Includes flame sensor assembly and associated hardware as supplied in the kit Replacement part matched to specific Lennox furnace models listed in Lennox documentation Compatibility & Applications: Intended for use on Lennox gas furnaces that specify 52W29 / LB-74940A in the official

Key Specs

• Product Type: Flame Sensor

Fitment Notes

Captured equipment fit data references models including G40DF-24A-045-3, G40DF-24A-045-7, G40DF-24A-045-9, G40DF-24A-045X-2, G40DF-36A-045-14, G40DF-36A-070-2, G40DF-36A-070-5, G40DF-36A-070-6, G40DF-36B-090-10, G40DF-36B-090-11, G40DF-36B-090-14, G40DF-36B-090-2. Verify the complete unit model and service manual before installation.

Expert Verdict

Reviewed by the SuperArbor Pro Desk: choose this part when the existing component label and unit documentation match 52W29 and the spec set above. It is best suited for targeted HVAC service repairs where exact fitment matters more than broad universal compatibility.

FAQs

What is the Lennox 52W29 used for?

It is a flame sensor for compatible Lennox HVAC equipment. Match the part number 52W29 and the equipment service literature before ordering or installing.

Which specs should I verify before purchase?

Verify the spec set shown for this part: Product Type: Flame Sensor. The replacement should match the existing component and the unit documentation.

How do I confirm this is the right replacement?

Compare the part number 52W29, the flame sensor description, and any unit model references with the original component and the service manual.

Which equipment models are referenced in the fit data?

Captured fit data references models such as G40DF-24A-045-3, G40DF-24A-045-7, G40DF-24A-045-9, G40DF-24A-045X-2, G40DF-36A-045-14, G40DF-36A-070-2. Treat this as a fitment aid and verify the complete model list in the equipment documentation.

Who should install this HVAC component?

A qualified HVAC technician should install and test the flame sensor. Disconnect power first, follow lockout procedures, and confirm safe operation after replacement.

Safety and Installation Notes

Disconnect power before service. HVAC electrical and combustion-related components should be installed and tested by a qualified technician. After installation, confirm wiring, mounting, airflow or fluid routing as applicable, and normal system operation.