Lochinvar & A.O. Smith 100109941 Ignitor

The Lochinvar & A.O. Smith 100109941 is a high-grade Hot Surface Ignitor (HSI) engineered for precision ignition in high-efficiency commercial and residential water heaters. This silicon carbide ignitor serves as the direct OEM replacement part for legacy numbers 9004566105 and 9004566115. Designed to withstand extreme thermal cycling, this component ensures reliable burner light-off in Lochinvar Knight and A.O. Smith Cyclone series units. The 100109941 features a specialized ceramic base and high-temperature lead wires to prevent electrical arcing and insulation breakdown. For technicians performing HVAC troubleshooting, this 120V ignitor provides the specific resistance required by the integrated control board to prevent ignition lockout codes. Replacing a brittle or carbon-fouled furnace ignitor with this genuine Lochinvar replacement part restores the system to factory specifications, ensuring optimal combustion and preventing delayed ignition issues in condensing water heaters.

• Direct OEM Compatibility: Engineered as the updated replacement for 9004566105 and 9004566115, ensuring a perfect fit and correct voltage draw.
• Durable Construction: High-density silicon carbide element provides superior resistance to oxidation and localized hot spots.
• Enhanced Thermal Shock Resistance: Designed to handle rapid temperature fluctuations during the ignition sequence without cracking.
• Plug-and-Play Installation: Includes the correct terminal connector and ceramic insulator for a secure transition to existing wiring harnesses.

Why is my A.O. Smith Cyclone showing an ignition failure code?
An ignition lockout is often caused by a cracked or high-resistance hot surface ignitor. If the 100109941 does not reach a visible glow within the specified trial-for-ignition period, the flame sensor will not detect a signal, causing the gas valve to close for safety.

Can I use a universal ignitor instead of the 100109941?
Universal ignitors often have different amp ratings and physical dimensions. Using the genuine Lochinvar 100109941 is critical to maintain the proper ignition sequence and avoid damage to the control board or improper burner alignment.

How sensitive is the silicon carbide element during installation?
The element is extremely fragile. Avoid touching the black carbide surface, as skin oils can create hot spots that lead to premature failure. Always handle the part by the ceramic base.

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.