Lochinvar & A.O. Smith 100074412 Limit Switch

As a specialist in Lochinvar and A.O. Smith boiler parts, I know that maintaining system safety is non-negotiable for any HVAC contractor. The Lochinvar & A.O. Smith 100074412 Limit Switch is a critical high-temperature protection component designed to monitor heat exchanger conditions and provide a failsafe shutdown if temperatures exceed safe operating parameters. This genuine OEM 100074412 high limit switch is a direct replacement for various residential and commercial water heating systems, including specific tankless units from Takagi, State, and American Water Heaters. It effectively replaces legacy part numbers EM212 and 319143-228, restoring the electrical circuit integrity required to prevent catastrophic overheating. Whether you are servicing a Lochinvar pool heater or an A.O. Smith power vent unit, using this precise thermal limit switch ensures the equipment operates within factory specifications. Don’t compromise on field reliability; installing exact HVAC high limit controls is the only way to ensure the long-term safety and performance of high-efficiency hydronic systems.

• Direct OEM Replacement: Replaces part numbers 100074412, EM212, and 319143-228 for a perfect fit and zero-leak installation.
• Critical Safety Protection: High-limit functionality prevents the system from exceeding maximum thermal thresholds, protecting the heat exchanger from damage.
• Broad Compatibility: Engineered for use across Lochinvar, A.O. Smith, and Takagi tankless and conventional water heating models.
• Industrial-Grade Construction: Built to withstand the rigorous temperature cycles found in commercial and high-demand residential heating applications.
• Fast Response Time: Features a high-sensitivity thermal element for rapid circuit interruption during over-temp events.

• How do I know if the 100074412 high limit switch is tripped? Check for continuity across the terminals. If the switch shows an open circuit at room temperature, it has likely tripped and reached its end-of-life status.
• Is this 100074412 switch a manual or automatic reset? This specific high limit switch is a safety device designed to break the circuit; always verify your specific unit's wiring diagram to determine if the control board requires a manual reset after the switch is replaced.
• Can I use this limit switch on other brands? This part is universal across several brands under the A.O. Smith umbrella, including Takagi and Lochinvar. Always cross-reference your model number to confirm this is the correct high-limit control for your equipment.

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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.