Lochinvar & A.O. Smith 100111057 Switch

The Lochinvar & A.O. Smith 100111057 Blocked Inlet Switch is a critical safety component designed for high-efficiency commercial water heaters and boilers, including the Cyclone Xi BTH and Shield series. This normally closed (NC) pressure switch monitors the combustion air intake, ensuring the blower assembly receives adequate airflow for safe operation. Engineered with a dedicated 0.85" W.C. trip point, it immediately breaks the safety circuit if an obstruction is detected in the air piping, preventing incomplete combustion or hazardous flue gas conditions. As an OEM blocked inlet air pressure switch, it provides the precise calibration necessary to avoid nuisance lockouts while maintaining strict adherence to manifold pressure requirements.

For field technicians, this part is the direct replacement for legacy SKU 9006281015. It is commonly utilized in A.O. Smith Cyclone BTH models (60-120 through 100-250) and Lochinvar Shield SNA/SNR units. When troubleshooting Error Code E10 (Air Switch Open) or E08 (Louver Proving Switch) on integrated control boards, verifying the integrity of the 100111057 switch is a standard diagnostic step. This switch is built to withstand the demanding cycles of commercial gas-fired applications, ensuring the combustion process remains within technical tolerances.

Key Benefits:

• Precise Safety Calibration: Factory-set at 0.85 Inch Water Column to detect intake blockages before combustion quality degrades.
• Broad Compatibility: Fits A.O. Smith Cyclone Xi, State, and Lochinvar Shield commercial heating systems.
• Robust Construction: Designed for high-cycle reliability in commercial gas water heaters and boiler intake systems.
• Failure Prevention: Proactively interrupts the ignition sequence if the feeder air inlet supply is compromised by debris or ice.

Common Questions:

• How do I troubleshoot an E10 or "Air Switch Open" error? Confirm the intake PVC is clear of obstructions, check the silicone tubing for moisture or cracks, and use a manometer to verify if the 0.85" W.C. threshold is being met during the pre-purge cycle.
• Is this switch compatible with LP and Natural Gas units? Yes, the 100111057 operates on the air-intake side of the assembly and is compatible with both fuel types provided the appliance model matches.
• Can I use an aftermarket universal switch? It is not recommended. This OEM blocked inlet switch is calibrated to a specific pressure; using a generic part can lead to dangerous operation or frequent system lockouts.

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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.