Lochinvar & A.O. Smith 100109932 Switch

The Lochinvar & A.O. Smith 100109932 Blocked Outlet Switch is a critical safety component designed for high-efficiency condensing boilers and water heaters. As a normally closed pressure switch, this device monitors backpressure within the venting system to ensure toxic flue gases are properly evacuated. If the vent becomes obstructed or the condensate drain system fails, the 100109932 interrupts the burner circuit, preventing unsafe operation and heat exchanger damage. This authentic OEM replacement part is built to precise tolerances, ensuring exact differential pressure setpoints required for Lochinvar Knight and A.O. Smith Cyclone models. Field technicians should verify the WC (water column) rating and electrical terminals during installation to maintain system integrity. Replacing a fouled or failing blocked flue switch with this genuine component restores the factory safety sequence and prevents nuisance lockouts caused by mechanical fatigue in older sensors.

• Ensures venting safety by detecting flue obstructions or high backpressure conditions.
• Direct OEM replacement for cross-referenced Lochinvar and A.O. Smith part numbers.
• Durable construction withstands the corrosive environment of condensing boiler exhaust.
• Precision-calibrated pressure setpoints reduce diagnostic errors and intermittent fault codes.
• Critical for maintaining ASME and ANSI safety standards in commercial water heating applications.

What causes a blocked outlet switch to trip on a condensing boiler?
Trips are typically caused by physical obstructions in the PVC venting, improper slope leading to condensate backup, or excessive wind shear triggering the pressure differential sensor.

Can I bypass the 100109932 switch for troubleshooting?
Bypassing safety switches is never recommended for permanent operation. Use a manometer to verify actual vent pressure versus the switch rating to determine if the issue is the switch or the venting system.

Is this switch compatible with Lochinvar Knight XL models?
Yes, the 100109932 is the standard blocked outlet switch for various Knight and Cyclone series, but you should always check your specific model and serial number in the service manual.

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.