Quiet Operation: Precision-engineered ceramic components provide near-silent fluid circulation

This industry-standard code indicates the switch opens at 170°F (L170) and has a 50-degree differential

Lead-Free Certified: Meets all current plumbing standards for potable water applications

Key Benefits OEM Compatibility: Specifically designed to match the electrical and flow requirements of Utica and Dunkirk boiler chassis

032" orifice optimized for stable natural gas combustion and reliable flame rectification

Lochinvar & A.O. Smith 100112429 Switch R-407A Quiet Operation: Precision-engineered ceramic componentsThe Lochinvar & A. O. Smith 100112429 Blocked Flue Switch is a critical safety component designed for high efficiency water heaters and commercial boilers. As a normally closed thermal switch, it monitors the venting system for atmospheric pressure imbalances or physical obstructions that could lead to dangerous carbon monoxide accumulation. Engineered for precision, this OEM replacement part triggers a system shutdown if it detects flue gas backup,