Lochinvar & A.O. Smith 100166232 Pressure Switch

The Lochinvar & A.O. Smith 100166232 Pressure Switch is a critical safety component designed for precise atmospheric monitoring in high-efficiency boiler and water heater systems. Engineered with a 1.05" WC fixed set point, this SPDT (Single-Pole Double-Throw) switch ensures the inducer motor is generating sufficient negative pressure to safely vent combustion gases before allowing the ignition sequence to proceed. As a direct OEM replacement part, it maintains the exact calibration required for the SMART SYSTEM control logic found in Lochinvar Knight and A.O. Smith commercial units. Modern HVACR technicians rely on this switch to prevent common pressure switch fault codes and flame failure lockouts caused by venting obstructions or diaphragm fatigue. Its robust construction and USA-made reliability make it the professional choice for restoring boiler combustion safety and operational efficiency in demanding commercial and residential hydronic applications.

• Precise 1.05" WC Rating: Factory-calibrated to ensure accurate proving of the combustion air blower.
• SPDT Switch Configuration: Provides versatile electrical signaling for both normally open and normally closed circuit requirements.
• OEM Compatibility: Replaces obsolete part number PRS30012, ensuring a perfect fit without modification.
• System Security: Prevents hazardous gas buildup by interlocking the gas valve with proper flue venting.
• Durable Construction: Built to withstand the high-cycle demands of modern condensing boilers and high-recovery water heaters.

What are the symptoms of a failing 100166232 pressure switch?
Technicians typically observe the inducer motor running indefinitely without the igniter glowing, or the control board displaying specific pressure switch stuck open or blocked flue fault codes. Short cycling or mid-cycle lockouts are also frequent indicators of a drifting set point.

How do you test this switch for proper functionality?
Using a manometer and a multimeter, verify that the SPDT contacts close at exactly 1.05 inches water column. Check for continuity across the terminals when the inducer is active and ensure there are no cracks in the pressure tubing or moisture buildup in the diaphragm housing.

Can I use a universal pressure switch as a substitute?
It is not recommended. This part is calibrated to a specific 1.05" WC threshold vital for the safety timing of the ignition control module. Using a switch with an incorrect rating can lead to incomplete combustion or dangerous delayed ignition scenarios.

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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.