Lochinvar & A.O. Smith 100074696 Computer Board

The Lochinvar & A.O. Smith 100074696 Computer Board is a critical genuine OEM replacement part engineered for high-efficiency tankless water heater control. Specifically utilized in Takagi T-H3-DV and T-H3-OS equivalent models, including the ATIO-540H series, this Computer Board 540 manages the modulation of the gas valve and fan speed to maintain precise discharge water temperatures. When troubleshooting water heater error codes such as the 101 or 991, replacing a faulty logic board with this factory-authorized 100074696 circuit board is essential for restoring proper ignition sequences and safety limit monitoring. This board ensures seamless communication between the remote controller and the internal thermistors, providing the reliable thermal processing required for commercial and residential high-demand applications.

• Exact OEM Integration: Direct drop-in for 100074696 and Computer Board 540, eliminating the field-modification risks associated with universal components.
• Advanced Modulation Control: Optimizes fuel-to-air ratios across the full firing range of Lochinvar and A.O. Smith water heaters.
• Diagnostic Capability: Designed to interface with onboard LED displays for rapid fault isolation and system status tracking.
• Heavy-Duty Circuitry: Built with high-grade capacitors and heat sinks to withstand the high-temperature environments of sealed combustion chambers.

Is this board compatible with both indoor and outdoor 540H models?
Yes, this tankless water heater computer board is designed to support the 540H series architecture used in both A.O. Smith ATI-540H (indoor) and ATO-540H (outdoor) configurations.

Does this part solve "no ignition" or "fan motor" communication errors?
While a replacement computer board often resolves communication failures, technicians should first verify that the 100074696 is receiving proper line voltage and that all wiring harnesses to the proportional gas valve are intact.

Does this board require firmware programming during installation?
No, this is a plug-and-play OEM control board. However, ensure the dip switch settings on the new board are configured to match the original unit's altitude and gas type specifications.

This item is not eligible for free shipping.

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.