Lochinvar & A.O. Smith 100166090 Pressure Switch

The Lochinvar & A.O. Smith 100166090 Pressure Switch is a critical safety component designed for high-efficiency boilers and water heaters. As a veteran technician knows, this OEM replacement part is essential for verifying proper blower operation and flue venting before the ignition sequence begins. It functions by monitoring the differential pressure within the combustion chamber, ensuring that the combustion air blower is moving sufficient air to safely exhaust flue gases. If the 100166090 air pressure switch fails to close its contacts, the integrated control module will halt the firing cycle, preventing hazardous conditions such as blocked flues or inducer failure. This specific switch is engineered to meet the exact set-point requirements of Lochinvar Knight and A.O. Smith Cyclone models, providing a precise pressure switch calibration that aftermarket universal parts often fail to replicate. Utilizing this genuine HVAC universal pressure switch equivalent ensures seamless system compatibility and maintains the operational integrity of your commercial or residential heating equipment.

• Precise Set-Point Accuracy: Factory-calibrated to ensure exact pressure sensing for specific Lochinvar and A.O. Smith venting configurations.
• Enhanced System Safety: Prevents ignition if the inducer fan or venting system is obstructed, protecting the heat exchanger from damage.
• Durable OEM Construction: Built to withstand the high-temperature environments of condensing boilers and power-vented water heaters.
• Direct Fit Replacement: Eliminates the need for mounting bracket modifications, ensuring a fast and reliable contractor installation.

How do I know if my 100166090 pressure switch is bad?
If your unit displays a "failed to prove" or "air pressure" fault code, check for 120VAC or 24VAC across the leads after the blower starts. If the blower is running but the contacts remain open, it likely needs replacement.

Can I use a universal switch instead of the 100166090?
It is not recommended. This switch has a specific WC (Water Column) rating required for the safety logic of the control board. Using an incorrect set-point can lead to frequent nuisance trips or unsafe operation.

Does this switch handle positive or negative pressure?
This model is designed to monitor differential pressure, sensing the vacuum created by the inducer or the positive pressure in the burner box, depending on the specific appliance's design.

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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.