Lochinvar & A.O. Smith 100166242 Pressure Switch

The Lochinvar & A.O. Smith 100166242 Pressure Switch is a critical safety component designed for precise draft and combustion monitoring in high-efficiency heating systems. Set to a fixed .27" WC (Water Column) trip point, this SPDT (Single Pole Double Throw) switch ensures that the inducer motor or blower is generating the correct static pressure before allowing the ignition sequence to proceed. As a veteran tech, you know that a failing switch often results in "no-flame" calls or pressure switch lockout codes on the SMART SYSTEM control board. This genuine OEM part is the factory-authorized replacement for the discontinued PRS30023, maintaining the exact calibrated response required for modern condensing boilers.

This Lochinvar low air pressure switch is engineered for rugged durability in residential and commercial applications, including the Lochinvar Knight and Copper-Fin boiler series (CB, CW, CS models). Whether you are troubleshooting air intake obstructions or verifying flue gas venting integrity, the 100166242 pressure switch provides the reliable electrical contact closure needed to prevent hazardous operation. It is compatible with a wide range of A.O. Smith water heaters and Lochinvar hydronic equipment where a .27" WC SPDT configuration is specified by the manual.

• Direct OEM Replacement: Identical fit and function for part number PRS30023, ensuring zero-mod installation.
• Precision Calibration: Factory set at .27" WC to maintain strict safety tolerances for condensing boilers.
• Versatile SPDT Logic: Supports both normally open and normally closed circuits for advanced system diagnostics.
• System Protection: Effectively monitors for blocked drains, venting issues, or blower failure to prevent incomplete combustion.
• Heavy-Duty Construction: Built to withstand the high-cycle demands of commercial HVACR environments.

• How do I verify if the 100166242 is the right switch? Check the label on your existing part. If it specifies a .27" WC setpoint and SPDT configuration, or references PRS30023, this is the correct technical match.
• Will this fix a "Pressure Switch Did Not Close" error? While often the culprit, verify your venting and hoses for blockages with a manometer before replacing. If the blower is running but the circuit remains open, the switch has likely failed.
• Can I use this on different boiler brands? While common in Lochinvar and A.O. Smith units, it can be used in any system requiring a .27 inch water column trip point, provided the mounting and port sizes match.

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.