Lochinvar & A.O. Smith 100109355 Ignitor Assembly

The Lochinvar & A.O. Smith 100109355 Ignitor Assembly is a mission-critical hot surface igniter (HSI) replacement designed for high-efficiency natural gas (NG) water heaters. Engineered to meet strict OEM specifications, this assembly functions as the primary ignition source for the burner, ensuring reliable light-off and consistent flame rectification. As the direct updated replacement for the legacy 9003626005 part number, the 100109355 features a stamped steel burner mount and an integrated flame sensor for precise signaling to the control board. This specific Natural Ignitor Assembly 75 is built to withstand the high-temperature cycles common in residential and light commercial Lochinvar and A.O. Smith units, including the GPSH 40/50 series. For contractors performing a water heater repair, this assembly provides a drop-in solution to resolve common ignition failure codes and intermittent burner operation without the need for field modifications.

Key Benefits

• Direct OEM Replacement: Seamlessly replaces legacy part 9003626005, ensuring electrical and physical compatibility with the gas manifold.
• Integrated Flame Sensor: Includes a high-response flame sensor to prevent nuisance lockouts and ensure safe gas valve operation.
• High-Temperature Durability: The 75 Hot Surface Igniter element is constructed from robust materials to handle the thermal stress of frequent cycling.
• Simplified Installation: Designed with a plug-and-play wiring harness and a standard bracket for rapid field replacement by a qualified HVACR technician.

Common Questions

Is the 100109355 compatible with my specific water heater model?
This ignitor is specifically designed for Natural Gas (NG) units like the A.O. Smith GPSH 40/50 and equivalent Lochinvar models. Always verify compatibility using your unit's serial number, as it is not a universal ignitor.

What was the previous part number for this assembly?
This is the manufacturer-authorized updated version for the 9003626005. It provides the same ignition performance but with updated component durability.

Does this assembly include the flame sensor?
Yes, this is a complete igniter and flame sensor assembly, allowing for the simultaneous replacement of both critical components to ensure a reliable combustion 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.