Lennox 10P29 Thermocouple

The Lennox 10P29 Thermocouple is a mission-critical 30MV furnace flame sensor designed for standing-pilot gas-fired heating systems. This 30-inch universal thermocouple generates a millivolt signal—approximately 30 mV DC—to maintain the connection with the Pilotstat safety control power unit. Engineered for versatility, it is an OEM-level replacement for Lennox part numbers 78B72, 31C38, 11Z70, and 10P2901, as well as several Honeywell Q340A series models including the Q340A1082/U. As a veteran technician, you understand that reliable pilot flame sensing is the first line of defense against gas leaks. The 10P29 features a durable construction capable of withstanding the high thermal stress of constant pilot exposure while providing an 11/32-32 male nut connector for a secure fit into the gas valve. The extended 30-inch lead length allows for flexible routing even in tight furnace cabinets, making it an ideal stock item for repairing Lennox G8, G12, and G16 series units or compatible systems from Allied, Armstrong, or Ducane.

• OEM Compatibility: Direct substitute for Lennox 10P29 and Honeywell Q340A1082, ensuring proper electrical matching with original gas valves.
• Universal Application: Includes a push-in clip, split nut, and adapter assembly to fit most pilot burner brackets.
• Reliable Millivolt Output: Maintains a consistent 30mV thermocouple signal to prevent nuisance shutdowns of the safety pilot loop.
• Extended 30" Reach: Long lead length simplifies installation in larger commercial or residential furnace heat exchangers.

What are the symptoms of a failing Lennox 10P29?
If the pilot light ignites but goes out immediately after releasing the gas control knob, the thermocouple is likely failing to generate the 30mV threshold required to hold the valve open.

Can I use this for water heaters as well as furnaces?
Yes, provided the water heater utilizes a 30mV standing pilot system and the 30-inch length is sufficient for the internal manifold routing.

How do I ensure a proper connection to the gas valve?
The male nut should be tightened finger-tight and then given an additional 1/4 turn with a 7/16-inch wrench. Over-tightening can damage the internal lead insulation and cause a short circuit.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.