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AVST Series Controller

AVST Series Controller

Advanced Variable Speed Transformer 

The AVST is an autotransformer based microprocessor controller.

  • Equipped with two 0-10VDC inputs; one input for BAS integration and the other input for connecting to a configurable LED User Interface
  • Can be operated in BAS, Manual, or Automatic mode
  • Utilizes dedicated temperature sensors that enable automatic adjustments to fan speed based on the temperature differential between these sensors

ZOO Fans’ Advanced Variable Speed Transformer Controller is an autotransformer based microprocessor controller designed to provide various options for the control of ZOO Fans. This Controller supports dynamic speed control for quiet, variable speed operation of the fans, and eliminates the undesirable motor hum often associated with Triac controllers. The fans can be controlled via Building Automation Systems (BAS), Manually (MAN), or Automatically (AUTO) with the addition of two dedicated temperature sensors. AUTO operation is based on the temperature difference (delta T) between these two sensors, typically placed near the floor and the ceiling. Fan speed and airflow are automatically controlled, based on the delta T and on the ceiling height as programmed via the configurable User Interface. Dynamic management of fan speed via the AUTO function or via BAS, typically results in fans running at lower speeds overall, while still maintaining thermal equilibrium in the space. By defaulting to LOW fan speed instead of OFF, constant background mixing continues to maintain comfort levels and save energy by supporting existing HVAC.

Automatic Mode


To maintain equilibrium, the ZOO Fans AVST Controller system will automatically speed-up and slow-down the fans based on Delta T and Ceiling Height.