Schneider Electric (Barber Colman) 2252-251 Temperature Transmitter

The Schneider Electric (Barber Colman) 2252-251 is a high-precision pneumatic temperature transmitter engineered for heavy-duty commercial HVAC applications. Featuring a 20-foot averaging element, this "one-pipe" device is specifically designed to eliminate inaccuracies caused by air stratification in large supply or return air ducts. It operates on a 3 to 15 psig output signal, providing a fixed 100-degree span over a 0 to 100°F temperature range. The construction utilizes a liquid-filled copper sensing element and beryllium copper feedback bellows to ensure superior linearity and signal stability, even in high-velocity airflow environments.

For the field technician, the 2252-251 offers a rugged cast aluminum base and a zinc-plated steel cover for long-term durability. It requires a 20 psig ±0.5 psi restricted supply of clean, dry air via a 1.0 scfh restrictor. With a maximum temperature of thermal element rating at 216°F, this duct mounting transmitter is resilient against temporary thermal spikes. The integrated averaging element provides a balanced temperature representative of the entire duct cross-section, preventing the short-cycling and control hunting often seen with single-point sensors.

Key Benefits

• Accurate Duct Averaging: The 20' averaging element compensates for thermal layers, ensuring the controller receives a true volumetric temperature reading.
• Mechanical Reliability: Beryllium copper feedback bellows provides high-cycle life and precise proportional pneumatic output.
• Field-Serviceable Design: Features a field-accessible "zero" adjustment screw for easy calibration during routine maintenance.
• Broad Compatibility: Seamlessly integrates with pneumatic control systems, receiver-controllers, and 3-15 psi gauges.
• Rugged Housing: Die-cast aluminum base and steel cover protect internal components from harsh mechanical room conditions.

Common Questions

The copper element should be installed in a serpentine pattern across the duct cross-section. Use mounting clips to secure the capillary and ensure a minimum bend radius of 1 inch to avoid kinking or fracturing the tube.

This is a "one-pipe" transmitter. It must be supplied with 20 psig of clean, dry, oil-free air through an external 1.0 scfh restrictor or a restrictor-tee. Failure to use a restrictor will lead to inaccurate output or device failure.

While designed primarily for duct mounting, it can be used in outdoor air intakes provided the case ambient temperature remains between 40°F and 140°F and the sensing element does not exceed its maximum rating of 216°F.

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.