Lochinvar & A.O. Smith 100109879 Ignition Module

The Lochinvar & A.O. Smith 100109879 Ignition Module is a critical OEM replacement part designed for high-efficiency gas-fired boiler and water heater systems. As a veteran-grade intermittent pilot ignition (IID) control, this 6-pin module manages the electrical sequence of the pilot light and main burner, ensuring precise timing and safe operation. It integrates a sophisticated flame sensing circuit to prevent hazardous gas accumulation by monitoring the combustion process in real-time. This module is engineered to drop into existing electrical harnesses for Lochinvar Copper-Fin II, Knight, and A.O. Smith Cyclone models, mitigating common ignition failure codes and lockout issues. By replacing a faulty 100109879 control board, technicians can restore reliable HVAC system performance and eliminate nuisance flame fail errors caused by degraded internal relays or component drift. Its compact design facilitates a direct swap, maintaining the tight electrical tolerances required by modern commercial and residential gas trains.

Key Benefits:

• Optimized Ignition Sequence: Provides consistent high-voltage spark for reliable pilot lighting across various manifold pressures.
• Enhanced Safety Monitoring: Features a built-in flame rectification circuit that immediately shuts off the gas valve if the pilot or burner flame is not detected.
• System Compatibility: Engineered as a direct fit for Lochinvar and A.O. Smith units, ensuring seamless integration with 24VAC control circuits.
• Durability: Industrial-grade components withstand the high-temperature environments typical of boiler control panels.

Common Questions:

How do I troubleshoot a 2-flash or 3-flash error on this module?
A 2-flash code typically indicates a flame signal without a call for heat, often due to a stuck gas valve or shorted electrode. A 3-flash code signalizes a hard lockout following failed ignition attempts; verify inlet gas pressure and inspect the spark ignitor gap before resetting the module.

Can the 100109879 replace 4-pin or 5-pin legacy modules?
This is a native 6-pin ignition module. Converting from older 4-pin or 5-pin configurations requires the correct Lochinvar adapter kit (part 100109676) to ensure the wiring harness pins align with the control's logic.

Does this module control the combustion blower?
While the module interacts with the overall safety string, it primarily governs the pilot and main gas valve timing. Ensure the air pressure switch has closed before the module initiates the spark sequence.

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.