Lochinvar & A.O. Smith 100208559 Sensor

The Lochinvar & A.O. Smith 100208559 Dual Immersion Sensor is a critical OEM replacement component designed for precision temperature monitoring in high-efficiency hydronic systems. This dual immersion sensor outlet assembly, also identified by part number TST20017K, utilizes a dual-element thermistor to provide the control board with real-time data on supply water temperatures. Engineered for technical compatibility with Lochinvar Copper-Fin II boilers (models CH 402 through 752) and CF water heaters, this 100208559 sensor ensures the system maintains optimal thermal stratification and prevents short-cycling. As a genuine Lochinvar replacement part, it meets strict factory specifications for resistance-to-temperature curves, ensuring seamless integration with the existing HVAC control system. For contractors performing boiler sensor troubleshooting, this unit is the standard solution for resolving "Sensor Open" or "Sensor Short" error codes on the diagnostic display. High-grade construction protects the internal sensitive elements from mineral scaling and corrosion within the immersion well.

• Direct OEM Compatibility: Specifically designed for Copper-Fin II boilers and CF water heaters, eliminating the risks associated with universal sensors.
• Dual-Element Precision: Provides redundant temperature tracking to ensure system efficiency and safe operating limits.
• Simplified Installation: Standard immersion sensor outlet design allows for a quick swap during routine maintenance or emergency repairs.
• Durable Housing: Rugged design withstands the high-temperature environments of commercial and residential hydronic heating systems.

Which boiler models are compatible with the 100208559 sensor?
This sensor is primarily used in Lochinvar Copper-Fin II CHN/CHL models ranging from 402 to 2072 and corresponding CFN/CFL water heaters.

What are the symptoms of a failing dual immersion sensor?
Technicians typically observe inconsistent firing, frequent "outlet sensor" faults on the control interface, or the system failing to reach setpoint due to inaccurate resistance feedback.

Does this part include the immersion well?
This part number typically refers to the dual immersion sensor probe; it is designed to fit into existing factory-installed wells on the outlet manifold.

This item is not eligible for free shipping.

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.