Lochinvar & A.O. Smith 100074640 Ignitor

The Lochinvar & A.O. Smith 100074640 Ignitor is a critical genuine OEM ignition component engineered for high-efficiency condensing water heaters and commercial boiler systems. Built to survive the rigorous thermal cycling of modern hydronic equipment, this black box ignitor assembly provides the high-voltage spark necessary for consistent burner ignition and reliable system startup. As a standard replacement for Lochinvar Knight boilers and A.O. Smith tankless units, it ensures the combustion process begins safely, maintaining the tight operational tolerances required by HVACR technicians and contractors.

Precision-manufactured by A.O.-Smith, this 100074640 igniter serves as a direct fit for numerous condensing models, including the T-H3, ATI, and GT series. Replacing a fouled or cracked ceramic ignitor with this authentic factory part eliminates common nuisance lockouts and "no flame" error codes. Its durable housing and robust lead connections are designed to handle the high-demand environments of both residential and commercial hydronic heating systems, ensuring long-term heating system performance and fuel efficiency.

Key Benefits:

• Direct OEM Replacement: Ensures exact compatibility with Lochinvar and A.O. Smith heating systems, maintaining original manufacturer safety certifications.
• Enhanced Reliability: Provides a consistent, high-intensity spark to prevent delayed ignition and combustion vibration in high-efficiency condensing models.
• Durable Construction: Features a high-grade black box assembly designed to withstand the humidity and heat found in commercial vent systems.
• Broad Compatibility: Fits various Takagi, State, and American Water Heater models, making it a versatile addition to a service truck inventory.

Common Questions:

How do I verify if the 100074640 ignitor is faulty?
Technicians should check for visible cracks in the ceramic or carbon buildup on the electrodes. Use a multimeter to verify the output voltage from the ignition control board during the trial-for-ignition phase to ensure the component is receiving the signal to spark.

Is this part compatible with tankless water heaters?
Yes, the 100074640 ignitor is specifically designed for A.O. Smith and Takagi tankless condensing units, providing the burner ignition required for these high-performance systems.

Can I clean the ignitor instead of replacing it?
While light oxidation can sometimes be removed with a fine abrasive, a cracked ceramic insulator or worn electrode requires immediate replacement to prevent permanent damage to the ignition transformer or flame sensing circuit.

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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.