Lochinvar & A.O. Smith 100109253 Pilot Assembly

The Lochinvar & A.O. Smith 100109253 Pilot Assembly is a critical OEM replacement component designed specifically for flammable vapor ignition resistant (FVIR) residential water heaters. As a veteran-grade 170 degree LP pilot kit, this assembly is engineered for liquid propane applications, ensuring precise flame rectification and reliable ignition sequences. It serves as the direct replacement for A.O. Smith 100109253 and Lochinvar 9003472005, maintaining the tight tolerances required for modern high-efficiency water heater maintenance. The kit typically includes the pilot tube, thermopile, igniter wire, and necessary gaskets to seal the manifold door, preventing combustion bypass. For technicians troubleshooting pilot light won’t stay lit issues, this assembly provides the millivolt signal stability necessary to hold the gas control valve solenoid open. When performing a water heater pilot assembly replacement, ensure the 170-degree orientation aligns perfectly with the burner bracket to ensure the flame properly envelopes the thermopile tip for optimal HVACR equipment performance.

• OEM Precision: Guaranteed compatibility with 100109253 and 9003472005 part numbers, eliminating the need for field modifications.
• Optimized Ignition: Specifically calibrated for liquid propane water heaters to provide a stable, consistent pilot flame.
• Safety Integration: Designed for FVIR systems to maintain the integrity of the combustion chamber seal.
• Complete Kit: Includes the 170-degree pilot bracket and high-temp lead wires for a standard professional install.

What causes this pilot assembly to fail?
Common culprits include soot buildup on the thermopile, a cracked ceramic insulator on the igniter, or a tripped thermal switch (TCO) due to restricted airflow in the flame arrestor.

Is this part compatible with natural gas units?
No. The 100109253 is strictly for LP (Liquid Propane) configurations. Using an LP pilot in a natural gas system will result in improper combustion and potential safety hazards.

Does this include the manifold door gasket?
Most 100109253 kits include the required mounting hardware and gaskets, but always inspect the existing burner access door gasket for damage during the teardown and replace if its seal is compromised.

This item is not eligible for free shipping.

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.