ACTUATOR; Analog VAV Differential Pressure Controller / Actuator

The compact analog electronic CSP-4702 is a combination controller-actuator designed primarily for use on pressure-independent VAV (Variable Air Volume) terminal units. It also has applications as an electronic static pressure controller. (For sample applications, see the application guides.)

Differential air pressure is sensed by an internal digital CMOS sensor connected via 1/4" FR tubing to an SSS-1000 series airflow sensor. The 0 to 2" wc (0 to 500 Pa) differential pressure sensor is internally linearized and temperature compensated for high accuracy down to very low pressures.

The CSP-4702 offers full-range flow control of VAV terminal units when used with the CTE-5202 electronic room thermostat. Air flow control limits may be set at the thermostat or internal to the CSP-4702. An adjustable mechanical stop is also included.

The CSP-4702 accepts a 2 to 10 VDC control signal from the thermostat. “Anti-jitter” circuitry significantly reduces hunting and needless wear on the actuator and damper components (from unnecessary miniscule position changes caused by undamped analog input signals). It also provides a 16 VDC output supply to power the thermostat and a 1 to 5 VDC voltage output that is proportional to the sensed differential pressure.

The CSP-4702 mounts directly to 1/4- to 5/8-inch (6 to 16 mm) round shafts or 1/4- to 7/16-inch (6 to 11 mm) square shafts, eliminating the need for expensive and complicated linkages. A non-rotation bracket, to prevent lateral movement, is included. For troubleshooting and setup, internal status LEDs (under the cover) indicate green for opening and red for closing. Factory-set clockwise rotation-to-close can be reversed by changing a jumper position. A gear disengagement button allows easy manual positioning of the actuator.

NOTE: Air flow volume is determined from the differential pressure by the formula Volume (in "cfm") = the K factor of the VAV box multiplied by the square root of the differential pressure (in "wc"). The K factor should be in the information supplied by the VAV box’s manufacturer.