Lochinvar & A.O. Smith 100109846 Limit Switch

The Lochinvar & A.O. Smith 100109846 is a 90-150F M/R limit switch engineered for high-precision thermal protection in residential and commercial water heating systems. As a critical safety component, this manual reset thermostat monitors air or water temperature to prevent overheating conditions that can lead to equipment failure or hazardous operation. It is specifically designed for cross-brand compatibility, serving as a direct replacement part for A.O. Smith and Lochinvar units, including the ECRS50 model series.

This HVAC high limit switch operates within a fixed 90°F to 150°F temperature range, ensuring the system stays within safe thermal parameters. The manual reset (M/R) functionality is a vital safeguard; once the 150°F threshold is breached, the switch locks out the heating circuit, requiring a technician to inspect the system before restoring operation. This 100109846 limit switch features a robust 5-screw terminal configuration for secure electrical terminations in demanding environments. Utilizing genuine Lochinvar and A.O. Smith replacement parts ensures that the system's original safety listings and operational efficiencies are maintained without the risks associated with generic alternatives.

Key Benefits:

• Compatible with Lochinvar and A.O. Smith models such as the ECRS50 water heater.
• Fixed 90-150F temperature range provides consistent thermal regulation and prevents over-temperature incidents.
• Manual reset (M/R) feature forces a system check after a high-limit trip, enhancing overall site safety.
• Designed for both residential and commercial heating systems, offering versatile application across multiple platforms.
• Durable electric thermostat limit switch construction ensures reliable cycling and long-term performance in high-duty cycles.

Common Questions:

What causes a manual reset limit switch to trip?
A trip is typically triggered by restricted airflow, sediment buildup in the tank, or a malfunctioning primary thermostat. Because this is a manual reset switch, the system will remain offline until the button is depressed by a technician.

Is the 100109846 switch compatible with other brands?
While primarily designed for A.O. Smith and Lochinvar equipment, compatibility is determined by the specific 90-150F thermal requirements and the 100109846 part number specifications. Always verify the manufacturer's manual.

Can I bypass this limit switch if it keeps tripping?
No. Bypassing a safety limit switch creates a significant fire and explosion risk. If the switch frequently trips, it indicates an underlying thermal issue that must be diagnosed and repaired.

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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.