Daikin AVV Installation And Maintenance Manual page 58

Controls by Others - Variable
Airflow
An optional EC motor with "variable fan speed control"
allows a field provided DDC controller to modulate the
unit airflow between 50% and 100% of nominal unit
airflow in a single zone variable air volume sequence.
In continuous fan mode the benefits of Single Zone VAV
include sound reduction, energy savings, and consistent
and precise temperature control for improved comfort
with better air mixing and less stratification. In humid
climates, the ability to deliver a wide range of fan speeds
is particularly effective for de-humidification.
Note: This option is not available with MicroTech controls.
Figure 118: 0-10VDC Variable Fan Speed Control
IM 817-7
100
90
80
70
60
50
0 2
Making Control Connections
For field provided control wiring connections refer to the
appropriate control wiring schematic,
60.
Connect the field 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% airflow at 2vdc and a maximum 100%
airflow at 10vdc as shown in
input signal to 0vdc will cause the motor to turn off. Care
should be taken when using variable airflow on units with
DX cooling as lower airflow may increase the risk of coil
freeze-up. Variable airflow control should not be used on
units with electric heat.
4 6
0-10 VDC Control Signal
58
page 59
Figure 120. Reducing the
8 10
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