The Lochinvar & A.O. Smith 100208503 Module is a critical ignition control module designed for high-performance direct spark ignition within EB and EW series water heaters and commercial boilers. Specifically engineered for Lochinvar EB/EW 100-300 models, this 120 VAC component manages the precise timing of the hot surface igniter and gas valve to ensure consistent combustion cycles. As a cross-referenced replacement for RLY2400 and RLY2400K, it maintains system integrity in high-efficiency commercial water heater parts ecosystems. For field technicians, this module offers a drop-in solution to resolve soft lockout issues caused by flame sensing failures or erratic spark signals. The robust internal circuitry is designed for the demanding duty cycles of Copper-Fin II and similar atmospheric or power-vented units, providing the reliable 24 VAC valve control and 120 VAC inducer fan sequencing required for code-compliant operation. Integrating this Lochinvar ignition module eliminates common ignition failure codes and restores the manufacturer’s specified heating sequence. Key Benefits Direct Compatibility: Engineered as the definitive OEM replacement for 100167710, RLY2400, and RLY2400K, ensuring no field modifications are required. Optimized Ignition Sequence: Controls the trial-for-ignition period and flame sensing current to prevent nuisance ignition failure lockouts. Enhanced System Reliability: Built to handle the voltage fluctuations and thermal demands of EB/EW 100-300 series commercial boilers. Diagnostic Feedback: Features integrated LED status indicators to streamline troubleshooting for HVAC contractors during service calls. Common Questions Is the 100208503 compatible with older RLY2400 models? Yes, the 100208503 is the current manufacturer-designated replacement for the RLY2400 and RLY2400K. It provides the same electrical footprints and mounting specifications. What causes this ignition module to trigger a "Hard Lockout"? A hard lockout typically occurs after multiple failed trials for ignition. Technicians should verify flame sensor cleanliness, proper grounding of the ignition cable, and stable 24 VAC supply voltage before resetting the module. Does this module control the blower motor directly? Yes, this module manages the timing for the 120 VAC blower inducer and ensures the air pressure switch is closed before initiating the hot surface ignition 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.
