Johnson Controls T-4506-217 Thermostat

The Johnson Controls T-4506-217 is a precision-engineered dual temperature pneumatic thermostat designed for reverse acting control in commercial HVAC systems. This horizontal-mount controller manages both day/night changeover and summer/winter transitions without an integrated indexing switch. Operating on a 13 to 25 psig supply pressure range, the unit is calibrated for an automatic switchover at 17 psig. Featuring a high-efficiency 400 SCIM flow capacity and a low 20 SCIM air consumption rate, the T-4506-217 ensures rapid response for pilot-positioning terminal equipment or direct-actuated valves. The dual dials provide a versatile 55 to 85 degree dial range, allowing for distinct setpoints in energy-saving modes. Built for longevity in rigorous environments, this Johnson Controls pneumatic control utilizes a sensitive bimetal element to maintain stable proportional control. It is a drop-in replacement for legacy pneumatic wall thermostats requiring high-flow performance and reliable dual-pressure logic in reverse acting HVAC configurations.

• Dual Setpoint Logic: Facilitates seamless transitions between two distinct temperature settings based on supply air pressure.
• High Flow Capacity: The 400 SCIM rating ensures fast actuation of dampers and valves, reducing lag in large zones.
• Air Conservation: Minimal 20 SCIM consumption reduces the overall load on the pneumatic compressor system.
• Direct Manual Override: Precision-calibrated dials allow for field-accurate adjustments within the 55-85°F range.
• Universal Mounting: Designed for horizontal installation, compatible with standard Johnson Controls wall boxes and terminal fittings.

How does the switchover function work on the T-4506-217?
The thermostat detects changes in main air pressure. It operates at one setpoint when supplied with 13-15 psig and automatically shifts to the second setpoint when the supply pressure is increased to 20-25 psig, with the internal switchover occurring at 17 psig.

Can this model be used in direct acting applications?
No, this specific model is hard-configured for reverse acting (RA) operation, meaning it decreases output pressure as the temperature rises. Ensure your terminal equipment (normally open/normally closed) matches this logic.

What is the primary difference between the T-4000 series and the T-4506 specifically?
The T-4506-217 is specifically a dual-temperature, high-volume output model. Unlike standard single-temperature T-4002 models, the T-4506 manages two independent setpoints, making it ideal for energy-efficient setbacks in commercial facilities.

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.