Siemens Building Technology 544-577-25 Sensor

The Siemens 544-577-25 Immersion Temperature Sensor is a high-precision field device engineered for liquid-medium sensing in hydronic and HVAC systems. Built around a Pt 1000 Ohm RTD element (Platinum 375 coefficient), this sensor provides highly accurate resistance-to-temperature conversion across a wide range from 0°F to 250°F (-18°C to 121°C). This unit features a 2.5-inch probe length and comes complete with a low-profile thermowell, ensuring reliable thermal transfer while protecting the sensing element from high-flow velocities and pressure variants. Designed for seamless integration with Siemens APOGEE and TALON automation systems, its 1k Ohm output ensures minimal signal degradation over long wire runs compared to standard thermistors. The lead-wire connection type simplifies field wiring within the conduit box, making it a staple for chilled water loop monitoring, boiler return diagnostics, and HVAC BAS installations where drift-free performance is critical for sequence-of-operations efficiency.

Technical Specifications and Benefits

• Precision Sensing: Utilizes a Pt RTD (1k Ohm) element for superior linearity and long-term stability in liquid applications.
• Integrated Hardware: Includes a matched 2.5-inch thermowell for rapid installation in high-pressure piping.
• Wide Operating Range: Rated for temperatures between 0°F and 250°F, covering most domestic hot water and cooling tower applications.
• Industrial Build: Durable probe construction designed to withstand corrosive hydronic environments without signal attenuation.
• Control Compatibility: Optimized for Siemens building controllers, providing a reliable 375a output signal for precise automation feedback.

Common Questions About the Siemens 544-577-25

Is the thermowell included with this model?
Yes, the 544-577-25 model includes the specific 2.5-inch thermowell required for immersion mounting, ensuring the sensor probe maintains direct contact with the well wall for accurate readings.

What type of controller input is required for this sensor?
This sensor requires a controller capable of reading 1000 Ohm Platinum RTD inputs with a 375-alpha coefficient. It is a passive resistance device, not a 4-20mA or 0-10V transmitter.

Can this be used for steam applications?
With a maximum temperature rating of 250°F (121°C), this sensor is suitable for low-pressure steam and hot water loops, provided the temperature limits of the sensing element are not exceeded.

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.