Lochinvar & A.O. Smith 100208464 Ignition Module

The Lochinvar 100208464 Ignition Module is a critical replacement control for Copper-Fin II series water heaters and boilers, providing precise electronic sequencing for hot surface ignition (HSI) systems. This HVACR control board is a direct functional equivalent to the RLY2402 and RLY2402K kits, designed to handle the rigorous demanding cycles of commercial and high-end residential Lochinvar and A.O. Smith units. It monitors flame rectification and manages the 24V circuit to ensure safe, reliable burner operation. When troubleshooting Lochinvar boiler ignition failure, replacing an outdated or faulty 100208464 prevents intermittent lockouts and inconsistent heating. This module is specifically engineered for compatibility with HSI series boilers and commercial pool heaters, including models from CH991 to CH2071 and CF991 to CF2071. By maintaining tight tolerances for trial-for-ignition timing, it protects the heat exchanger from unburned gas accumulation and optimizes thermal efficiency.

Key Benefits

• Direct OEM replacement for Lochinvar RLY2402 and RLY2402K ensures seamless fit and electrical integration without field modifications.
• Optimized for Lochinvar Copper-Fin II systems to maintain factory-spec sequence of operation and safety timings.
• Advanced flame sensing circuitry reduces nuisance lockouts common in aging HSI ignition systems.
• Robust construction resists the heat and vibration stresses typical of commercial water heater mechanical rooms.
• Simplifies HVAC troubleshooting by restoring reliable spark-to-burn or HSI-to-burn transitions in A.O. Smith and Lochinvar appliances.

Common Questions

Is the 100208464 compatible with older RLY2402 models?
Yes, the 100208464 is the current consolidated part number and is technically identical to the RLY2402 and RLY2402K. It serves as the direct replacement ignition module for those legacy components.

What are the symptoms of a failing ignition module in a Copper-Fin II?
Common indicators include the hot surface igniter glowing without the gas valve opening, frequent ignition lockouts (Error 1 or 2 on many digital controllers), or the burner dropping out immediately after a successful light-off due to poor flame rectification.

Does this module control the combustion blower?
This module primarily manages the ignition sequence and flame monitoring; however, in the Lochinvar wiring schematic, it operates in series with the limit string and air pressure switches to ensure the inducer is moving air before the hot surface ignition cycle begins.

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.