Lochinvar & A.O. Smith 100112148 Switch

The Lochinvar & A.O. Smith 100112148 Switch is a critical safety component designed for high-efficiency water heaters and boilers. As a normally open pressure switch, it monitors negative air pressure created by the combustion air blower, ensuring the unit only proceeds to ignition once a proper draft is established. This genuine OEM replacement part is engineered to meet 2" WC specifications, providing the precision required to prevent hazardous gas buildup and maintain optimal fuel-to-air ratios in modern sealed combustion systems.

For service technicians, the 100112148 is the go-to solution for troubleshooting ignition failures and short-cycling issues. It features a high-grade pressure switch diaphragm housed in a durable casing, designed to withstand the heat and moisture common in condensing units. This switch is frequently utilized in the Lochinvar Knight boiler series and compatible A.O. Smith industrial water heaters. By accurately detecting the induced draft, it protects the heat exchanger from thermal stress and ensures compliance with factory safety sequences.

• Ensures peak HVAC system performance by validating flue gas expulsion before the ignition cycle.
• Heavy-duty construction prevents pressure switch diaphragm failure caused by common heat cycling.
• Direct OEM replacement part ensures perfect fit and electrical compatibility with the control board.
• Helps resolve furnace error codes related to blocked flues or inducer motor malfunctions.
• Maintains safe negative air pressure levels for high-efficiency condensing applications.

What are the signs of a failing 100112148 pressure switch?
Common symptoms include the inducer motor running continuously without ignition, "pressure switch stuck open" error codes on the Smart System control panel, or the unit shutting down shortly after the burner fires.

Can I use a universal switch instead of the 100112148?
In high-efficiency Lochinvar and A.O. Smith equipment, using the exact OEM heating part is recommended to ensure the setpoint (2" WC) matches the manufacturer's logic for safe operation.

Does this switch resolve a "blocked flue" error?
If your exhaust is clear and the inducer is pulling a strong vacuum, the switch may be the culprit; however, technicians should always use a manometer to verify the draft before replacing the part.

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.