Johnson Controls T-4002-204 Pneumatic Thermostat

The Johnson Controls T-4002-204 is a professional-grade, high-volume output pneumatic thermostat engineered for precise temperature regulation in demanding commercial and industrial environments. This reverse acting pneumatic thermostat is designed specifically for vertical mount orientations, providing a proportional output signal to modulate pneumatic valves and damper actuators. It operates within a standard 55-85°F dial range, utilizing a single bimetal sensing element to ensure consistent thermal monitoring and responsive climate control. As a two-pipe pneumatic system component, it features dedicated supply and output air connections equipped with 5/32-inch barbed fittings for seamless integration with existing polytubing runs.

For technicians performing field calibrations, the T-4002-204 offers adjustable sensitivity ranging from 0.75 to 4 psig/°F, allowing for fine-tuned performance across a variety of HVAC pneumatic control systems. The unit is factory-calibrated for a 20 psig nominal supply pressure and includes pneumatic feedback with volume amplification to minimize lag and ensure accurate setpoint maintenance. Built to withstand mechanical stress, its vibration and shock resistant construction makes it a reliable replacement for older T-4000 series models. Whether managing heating or cooling loads, this Johnson Controls pneumatic controller provides the durability and technical precision required for critical facility automation.

Key Benefits

• High-Volume Output: Features an integrated volume amplifier for rapid response in large-scale pneumatic actuator applications.
• Broad Compatibility: Standard 5/32 in. barbed fittings facilitate easy retrofitting into established Johnson Controls pneumatic networks.
• Precision Calibration: Adjustable sensitivity and a clear 55-85F dial range enable exact terminal equipment modulation.
• Industrial Durability: Rugged design is specifically rated for vibration and shock resistance in mechanical rooms.
• Pneumatic Feedback: Enhances stability and accuracy by providing a proportional air signal that reduces hunting.

Common Questions

What is the difference between direct and reverse acting in this model?
The T-4002-204 is reverse acting, meaning the output pressure increases as the sensed room temperature increases, which is required for specific fail-safe or sequenced valve and damper configurations.

Can this thermostat be mounted horizontally?
No, this specific suffix (-204) is calibrated and labeled for vertical mount installation only; horizontal requirements would necessitate a different model within the T-4000 series.

What air pressure is required for operation?
This pneumatic room thermostat typically operates on a 20 psig nominal supply, with a functional range between 13 and 25 psig of clean, dry, oil-free compressed air.

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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.