Carrier LH31CM035 Pilot/Ignition Assembly

As a service tech, you know that a failed ignition sequence is one of the most common no-heat calls during the peak of winter. The Carrier LH31CM035 Pilot/Ignition Assembly is a genuine OEM replacement engineered for precision in high-efficiency gas furnaces and rooftop units. This intermittent pilot ignition system replaces older LH31CM023 units and features a factory-calibrated 0.018-inch orifice for an optimized fuel-air mixture. The integrated assembly includes the pilot burner, flame sensor (flame rod), and a spark electrode, all pre-wired with an 18-inch lead for a direct fit. Utilizing a White Rogers ignition control interface, this component ensures a steady pilot flame is established before the main gas valve opens, preventing delayed ignition and nuisance lockouts. Whether you are servicing a Carrier, Bryant, or Payne furnace, using this HVAC replacement part maintains the factory-specified safety sequence and combustion efficiency. The 18-inch wiring provides ample reach for standard hot surface ignition retrofits or traditional pilot burner assembly swaps in 48-series packaged units.

Key Benefits

• OEM Compatibility: Designed as a direct replacement for Carrier LH31CM035 and LH31CM023, ensuring proper alignment with the burner rack.
• Reliable Flame Sensing: The high-grade flame sensor prevents intermittent cycles by providing a consistent microamp signal to the control board.
• Precise Fuel Delivery: Features a fixed 0.018-inch orifice to maintain the correct BTU input for the pilot flame.
• Heavy-Duty Construction: Built with high-temperature alloys to resist carbon buildup and thermal stress in demanding residential heating environments.
• Simplified Installation: The inclusive design with 18-inch leads reduces field-wiring time and ensures a secure connection to the ignition module.

Common Questions

Is the pilot tubing included with this assembly?
Internal tech data confirms this is the pilot/igniter assembly only. You should reuse the existing 1/4-inch or 1/8-inch pilot tubing if it is clear of obstructions and the compression fittings are seated correctly.

Why is my furnace clicking but not lighting?
If the Carrier LH31CM035 electrode is sparking but the pilot fails to light, check for a clogged pilot orifice or inadequate gas pressure. If the pilot lights but the main burner doesn't follow, the flame sensor likely isn't detecting the flame.

Can I use this for both natural gas and liquid propane?
This assembly is factory-shipped for natural gas applications. If you are working on a propane conversion, verify that the 0.018-inch orifice matches the requirements of your conversion kit or the specific appliance rating plate.

Item is Non Cancelable / Non Returnable

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.