Lochinvar & A.O. Smith 100110001 Pressure Switch

As an HVAC technician, you know that a call for a pressure switch failure often points to more than just a faulty component—it’s a critical safety lockout. The Lochinvar & A.O. Smith 100110001 Pressure Switch is a factory-spec OEM replacement part designed to monitor inducer draft and flue gas venting. This .70" WC pressure switch is calibrated specifically for high-efficiency water heaters and boilers, ensuring the combustion blower is pulling a safe vacuum before the gas valve is energized. If your multi-meter confirms the switch isn't closing during the inducer motor run-up, this 100110001 (also referenced as A.O. Smith 9004634215) is the exact drop-in solution needed to restore the ignition sequence and maintain safe combustion. Built with a normally open contact configuration and a precision 0.70 inches of water column set-point, it eliminates the risks associated with universal parts that can cause nuisance trips or dangerous delayed ignition in Lochinvar Knight and A.O. Smith Proline systems.

• OEM Compatibility: Precision-calibrated for Lochinvar and A.O. Smith commercial and residential gas-fired units, preventing incorrect pressure readings.
• Enhanced Safety: Acts as a burner lockout mechanism, immediately shutting down the gas train if vent blockages or inducer fan failures are detected.
• Direct Replacement: Features a standardized mounting bracket and hose port orientation for fast, tool-friendly installation on a busy service route.
• Technical Precision: Holds an accurate .70" WC set-point, essential for maintaining the narrow operational parameters of high-efficiency gas equipment.

What are the symptoms of a bad .70" WC pressure switch?
Standard failure modes include the purging motor running continuously without the sparking or glowing igniter phase, or your diagnostic board throwing a "pressure switch stuck open" error code.

Is the 100110001 compatible with other brands?
This switch is an OEM part for A.O. Smith and Lochinvar. While it may look like other HVAC pressure switches, the 0.70" WC set-point is specific; always verify the technical data on the old switch label before swapping.

Can I bypass this switch for testing?
While a temporary jumper can diagnose a bad switch, never leave a unit running without a functioning vacuum switch, as it is the primary safety against carbon monoxide backup.

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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.