Johnson Controls T-4002-203 Pneumatic Thermostat

The Johnson Controls T-4002-203 is a high-performance direct acting pneumatic thermostat designed for precise temperature regulation in commercial HVAC systems. This vertical mount controller features a bimetal sensing element that provides a proportional output signal to modulate valves and damper actuators. Engineered for reliability in building automation systems, the T-4002-203 operates with a 55-85°F dial range and a high-volume output of 400 scim, ensuring rapid response to thermal load changes. It utilizes a 20 psig nominal supply pressure and includes 5/32-inch barbed supply and output air connections for seamless integration into existing pneumatic control loops. The unit's vibration-resistant construction and adjustable sensitivity—ranging from 0.75 to 4 psig/°F—make it a staple for technicians maintaining pneumatic legacy hardware or modern multi-zone environments.

• High Volume Output: Delivers 400 scim flow capacity for fast actuation of large pneumatic dampers and valves.
• Precise Calibration: Features pneumatic feedback for improved accuracy and stable proportional control.
• Field Versatility: Adjustable sensitivity slider allows for fine-tuning based on specific zone requirements.
• Durable Design: Bimetal sensor is shock and vibration resistant, meeting rigorous commercial specifications.

Is the T-4002-203 compatible with older T-4000 pipeheads?
Yes, this unit is designed to install directly onto existing T-4000 copper tube pipeheads or plastic terminal connectors using 5/32" OD tubing.

How do I adjust the sensitivity on this thermostat?
Technicians can move the sensitivity slider internally—left to increase or right to decrease—to achieve a range between 0.75 and 4 psig per degree Fahrenheit.

What is the factory calibration setting?
The instrument is factory-calibrated to provide an 8 psig output signal when the ambient temperature matches the setpoint dial at a 20 psig supply.

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.