Lochinvar & A.O. Smith 100170642 Temp Sensor

This Lochinvar & A.O. Smith 100170642 Temp Sensor is a critical OEM replacement part designed for high-efficiency hydronic systems and commercial water heaters. As a direct successor to the TST30011, this flue temperature sensor (also cross-referenced as 100170536 and TST20008) provides real-time thermal monitoring of exhaust gases. When installed in Knight XL boilers or A.O. Smith power-vented units, it communicates vital data to the control board to modulate burner firing rates and prevent heat exchanger damage from excessive flue temperatures. This specific boiler temperature probe includes the necessary mounting grommet to ensure a gastight seal at the venting interface. For field technicians, verifying the NTC thermistor resistance against the manufacturer’s ohm chart is essential when troubleshooting "flue sensor open" or "limit exceeded" fault codes. This genuine HVAC replacement sensor ensures your equipment maintains peak energy efficiency and meets factory safety standards during heavy-duty cycles.

• Precise Thermal Feedback: Delivers accurate NTC resistance signals to the integrated control platform for steady-state operation.
• Compatibility: Engineered for Lochinvar Knight XL (KB 400-801) and A.O. Smith commercial models, ensuring 100% plug-and-play fitment.
• System Protection: Acts as a primary safety limit to shut down combustion if flue gas temperatures exceed safe operational thresholds.
• Complete Kit: Shipped with the pre-installed grommet for immediate, leak-free installation in the exhaust manifold.

• Is the 100170642 compatible with older TST30011 installations? Yes, this part is the current direct replacement for the TST30011 and TST20008, maintaining identical electrical characteristics and physical dimensions.
• What does a 'Flue Sensor' error code typically indicate? Most often, a fault indicates either a fouled probe, loose wiring connections at the control board, or a sensor that has drifted out of its calibrated ohm range.
• Do I need to apply sealant to the grommet? No, the included grommet is designed to create a mechanical seal within the flue collector. Ensure the mounting surface is clean of debris before insertion.

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.