Greenheck vari-green Installation, Operation & Maintenance Manual page 8

Two Speed Assembly
Two Speed
Installation Overview: The two speed control is factory
mounted to the fan and may be set to provide any
two speeds the application requires. It also includes a
24 VAC transformer which has a dual voltage primary
(115/230V), selectable via a switch on the housing
near the power cable. The voltage will be factory set to
match the motor voltage.
1. A green LED will be illuminated when the 2-speed
control is powered.
2. There are two methods of toggling between speed A
and speed B:
a. Dry contact input - this utilizes an external
switching device such as a relay or SPDT switch
to toggle between the two speeds.
• Connect terminal "A" to "COM" for speed A.
• Connect terminal "B" to "COM" for speed B.
If no contact is made between either terminal the
motor will be off.
b. AC Digital input - this input allows an AC voltage
signal to be fed directly into the 2-speed control
to change speeds.
• Send 115-230V AC to L1 OR L2 for speed B.
• Send 115-230V AC to L1 AND L2 for speed A.
If no voltage is applied to either terminal, the
motor will be off.
c. DO NOT CONNECT BOTH DRY CONTACT AND
DIGITAL INPUTS SIMULTANEOUSLY.
3. To test fan operation before the external control
devices are installed, a jumper wire can be
connected between the COM and A or B terminal on
the dry contact input for fan operation.
8 Vari-Green Motor
Troubleshooting - Two Speed
1. Check all wiring connections to ensure they are
correct and secure.
2. Verify AC line voltage is present at the motor and
2-speed control.
3. Verify 24V AC is present at the 24V and COM
terminals of the "Motor" terminal block.
4. Measure DC voltage between the 0-10V and COM
terminals of the "Motor" terminal block. This voltage
should match the dial position of the active dial.
a. If using dry contact input - ensure contact closure
is connecting the proper terminals.
b. If using AC digital input - disconnect connector
from 2-speed control and measure voltage
between L1 and Neutral or L2 and Neutral.
Multiple motors on one control
See the table below for the recommended number of
motors to be driven from one controller. Note that the
controllers do not have the ability to distinguish between
more than one motor, therefore all motors will receive
the same control voltage.
Controls
Remote Dial
2 Speed
Constant Pressure
Temperature/Humidity
VOC
Maximum Motor Quantity
4
6
4
2
2
®