Source: Greenheck

A recent release in Greenheck’s Computer Aided Product Selection (CAPS) Program includes Hand / Off / Auto (HOA) for the Vari-Green product line. The new Vari-Green HOA control from Greenheck gives the user the ability to:

  • Run the fan in hand mode (speed defined at this device)
  • Enable / disable the fan

The fan can be enabled by using a dry contact closure or by providing a voltage (12-120V). This new capability means that the HOA can be the go-to between device to hook up any Vari-Green fan to just about any system. A programmable override setting is also included. The override will ignore other commands and send the fan to a defined speed. With only three buttons and an LED display, this compact accessory is functional and user-friendly.

Modes Defined

Hand Mode: Set motor speed manually in the HOA keypad. Use this mode for balancing, troubleshooting, or to operate fan before external controls are installed / operational.

Auto-Local Mode: Set motor speed using HOA control. The motor can start/stop remotely via dry input and/or voltage input.

Auto-Remote Mode: The remote device provides 0-10V signal for speed reference. The motor can start/stop remotely via dry input and/or voltage input.

Override: Voltage input will run the motor at speed set in the HOA keypad. This input will take precedence over every other signal/mode.

How to Select in CAPs

As a Control: You can select the HOA from the Vari-Green control drop down. This device is controlling the fan or it is passing a speed reference by others.

As an Accessory: Pick your Vari-Green control (remote dial, constant pressure, etc.) and apply the HOA as an accessory to the fan. The existing transformer box now lets you pick either a transformer or an HOA (mounted or shipped loose). The HOA now becomes an accessory to any other Vari-Green controls. These controls can be installed in many fans and mounted in the space.

Example Application

Let’s look at a typical scenario like a stairwell pressurization application. Suppose you have a Vari-Green exhaust fan. In the event of a fire, you want a constant pressure controller to modulate the fan speed to maintain 0.10 in. wg in that space. The HOA controller can accept the 0-10V signal from the constant pressure controller, but not pass the signal to the motor unless it receives a voltage or dry contact signal allowing the fan to run. The applications are endless with this device since it can be controlled by other equipment.

What this means for you: Easy integration with a lot less hassle.