P128AA-1C Johnson Controls Cutout

Overview

The Johnson Controls T-4752-205 is a pneumatic heating-cooling room thermostat designed to provide automatic changeover control for both heating and cooling systems in commercial HVAC applications. This dual-temperature, high-volume output thermostat operates on a pneumatic signal, modulating controlled devices in response to temperature variations. It is designed for horizontal mounting and features a single set point dial.

Features

• Provides automatic changeover between heating and cooling modes based on supply pressure changes.
• Dual-temperature bimetal sensing elements for proportional control.
• High-volume output capacity to efficiently modulate controlled devices.
• Pneumatic feedback mechanism ensuring operational accuracy.
• Robust construction engineered to be vibration and shock resistant.
• Horizontal mounting configuration with a single dial interface.

Specifications

• Control Type: Pneumatic
• Application: Heating and Cooling (Dual Temperature)
• Supply Pressure (Heating Mode): Nominal 15 PSIG (13 to 18 PSIG), Reverse Acting (REV)
• Supply Pressure (Cooling Mode): Nominal 20 PSIG (17 to 25 PSIG), Direct Acting (DIR)
• Switchover Pressure: Factory set at 17.5 PSIG (Adjustable from 15 to 20 PSIG)
• Sensitivity: Adjustable from 0.75 to 4.0 PSI/F° (Factory set at 2.5 PSI/F°)
• Output Flow Capacity: 400 SCIM (109 mL/s)
• Air Consumption: 20 SCIM (5.5 mL/s)
• Air Connections: Barbed fittings for 5/32 in. O.D. polytubing
• Operating Temperature Limits: -20 to 130°F (-29 to 54°C)
• Mounting Orientation: Horizontal

Applications

The T-4752-205 is ideal for individual space temperature control in commercial, institutional, and industrial facilities utilizing pneumatic HVAC systems. It is commonly applied in variable air volume (VAV) systems, fan coil units, and air handling units where automatic changeover between heating (reverse acting at 15 PSIG) and cooling (direct acting at 20 PSIG) is required from a single wall-mounted device.