Lochinvar & A.O. Smith 100110951 Probe

The Lochinvar & A.O. Smith 100110951 Probe is an essential OEM replacement part for commercial and residential water heating systems. As a Probe ECO/Thermostat, this dual-function component serves as both a temperature sensor and an Emergency Cut-Off (ECO) high-limit switch. It is engineered to monitor tank temperatures with high precision, providing real-time data to the control board to optimize thermal efficiency. Designed for integration with Lochinvar boilers and A.O. Smith water heaters, this 100110951 thermal probe ensures the system operates within safe parameters, triggering a lockout if temperatures exceed the 203°F safety threshold. For technicians, this HVACR sensor is a critical diagnostic component when troubleshooting "no heat" calls or cycling issues. Replacing a drifted or scaled-over probe restores accurate thermostatic control and prevents nuisance trips, maintaining the reliability of the water heater thermostat circuit without requiring extensive system modifications.

• Enhanced Safety: Integrated ECO high-limit functionality protects the system from overheating by providing a manual or automatic reset lockout.
• Precise Monitoring: High-accuracy NTC thermistor technology provides consistent resistance readings for tighter temperature regulation.
• Direct OEM Fit: Designed as a genuine Lochinvar 100110951 and A.O. Smith 100110951 replacement to ensure electrical and mechanical compatibility.
• System Efficiency: Reduces energy waste by eliminating wide temperature swings caused by unresponsive or fouled sensors.
• Durable Construction: Built to withstand the harsh environment of pressurized domestic hot water and hydronic heating systems.

What are the symptoms of a failing 100110951 probe?
Common signs include the water heater locking out on high-limit (ECO) errors, inaccurate water temperatures, or "out of range" resistance codes on the digital display. Technicians should check the probe resistance (Ohms) against the manufacturer’s temperature chart to verify calibration.

Is the 100110951 probe compatible with A.O. Smith BTX and GDHE series?
Yes, this replacement probe is commonly specified for high-efficiency series such as the A.O. Smith Cyclone and Lochinvar Knight and Shield products. Always cross-reference your specific model and serial number before installation.

How do I reset the ECO after a high-limit trip?
Once the tank temperature drops below the reset threshold (typically 120°F), the lockout can be cleared at the control board. If the probe continues to trip at normal temperatures, it likely requires replacement due to sensor drift.

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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.