Atlanta Counter VAV Controls Selection Guide

VAV Reset Controllers | Damper End Switches | Reversing Relays

CSC-300 Series VAV Reset Controllers

These CSC-3000 series reset volume controllers are designed for use on heating or cooling systems with (normally open or normally closed) VAV terminal units and (direct or reverse acting) thermostats. They are sub-master air velocity controllers. Each is equipped with separate adjustment knobs for minimum and maximum airflow setpoints.

Models are available with various reset start points. A master controller, typically a room thermostat, resets the CSC-3000 between the minimum and maximum velocity setpoints. The universal design of the CSC-3000 series is intended for new or replacement applications that call for direct or reverse acting reset on normally open or normally closed VAV terminal units

CSC-200 Series VAV Reset Controllers

The pneumatic CSC-2000 series are designed for use on VAV terminal units in HVAC systems. These are differential-pressure, sub-master controllers with adjustable minimum and maximum airflow settings. A master controller, typically a room thermostat, resets the CSC-2000 velocity setpoint.

Direct acting models are for normally open VAV terminal units. Reverse acting are for normal closed VAV terminal units. Each is equipped with separate adjustment knobs for minimum and maximum airflow settings. All models should be calibrated with the use of airflow measuring equipment.

The tables below illustrates the appropriate model for each application. If replacing a CSC-2001-22 or CSC-2002-22 (now obsolete), use the CSC-2001, CSC-2002, CSC-2003, or CSC-2004 and mount appropriately.

Direct Acting (Beige Controllers) for Normally Open Dampers

Reverse Acting (Gray Controllers) for Normally Closed Dampers

Damper End Switches

They are mounted on a horizontal damper shaft to provide opened/closed indication. Switch contacts are normal when the cable end of the switch is horizontal or above, and makes when the cable end drops more than 15º below horizontal. These switches are ideal for Building Automation System BAS and HVAC applications.

Reversing Relays

A reversing relay is designed for use in pneumatic control systems where the application requires reversing a signal from a controller. The same signal goes to the reversing relay, where it is reversed to an increase in pressure to the cooling valve. This closes the cooling valve.