Daikin AVV - Variable Airflow and Valve Control Wiring

IM 817-7 58 www.DaikinApplied.com
Controls by Others - Variable
Airow
An optional EC motor with “variable fan speed control”
allows a eld provided DDC controller to modulate the
unit airow between 50% and 100% of nominal unit
airow in a single zone variable air volume sequence.
In continuous fan mode the benets of Single Zone VAV
include sound reduction, energy savings, and consistent
and precise temperature control for improved comfort
with better air mixing and less stratication. In humid
climates, the ability to deliver a wide range of fan speeds
is particularly effective for de-humidication.
Note: This option is not available with MicroTech controls.
Making Control Connections
For eld provided control wiring connections refer to the
appropriate control wiring schematic, page 59 or page
60.
Connect the eld supplied controller to the harness
provided. A 0-10VDC fan control signal must be provided
between ground and wire 33. For RPM/data out signal,
connect controller to wire 34.
The variable fan speed scale is linear between a
minimum 50% airow at 2vdc and a maximum 100%
airow at 10vdc as shown in Figure 120. Reducing the
input signal to 0vdc will cause the motor to turn off. Care
should be taken when using variable airow on units with
DX cooling as lower airow may increase the risk of coil
freeze-up. Variable airow control should not be used on
units with electric heat.
Figure 118: 0-10VDC Variable Fan Speed Control
10
100
8426
50
60
70
80
90
0-10 VDC Control Signal
% Nominal Unit Airflow
0