Lochinvar & A.O. Smith 100108882 Pressure Switch

The Lochinvar 100108882 (also indexed under A.O. Smith 100108882) is a critical safety differential air pressure switch designed for commercial boilers and water heaters. Calibrated for a fixed setpoint of 1.10" W.C., this SPNO (Single Pole Normally Open) switch ensures the combustion blower is generating sufficient airflow before allowing the ignition sequence to proceed. As an OEM replacement part, it is engineered to maintain high-limit accuracy in condensing boilers and high-efficiency water heaters. Contractors should verify the WC setpoint against the manufacturer’s technical data plate to prevent nuisance lockouts or short-cycling. This unit features a rugged diaphragm housing and standard terminal connections for seamless integration into existing LOCHINVAR Knight or A.O. Smith Cyclone control circuits. Replacing a failing 100108882 pressure switch restores system reliability and prevents error code interruptions related to venting or air intake obstructions.

• Precise 1.1" W.C. Calibration: Ensures strict compliance with combustion safety parameters.
• OEM Compatibility: Exact replacement for A.O. Smith and Lochinvar part number 100108882.
• Durable Construction: Built to withstand the high-temperature environments of mechanical rooms.
• Reliable Switching: High-quality internal diaphragm ensures repeatable performance over thousands of cycles.

What causes a 1.1" pressure switch to fail?
Failure is often caused by moisture in the sensing tubes, cracked diaphragms, or carbon buildup in the venting system which prevents the pressure switch from closing.

Is this switch compatible with non-condensing units?
This switch is specifically calibrated for 1.1" WC requirements. Technicians must check the boiler specification manual to ensure the trip point matches the original equipment manufacturer's requirements.

Can I adjust the setpoint on the 100108882?
No, this is a factory-set fixed pressure switch. Attempting to adjust the setpoint can lead to unsafe combustion conditions or CO leaks.

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.