44
VAV control
With VAV control, the system is equipped with a duct
high limit transmitter. This transmitter sends a signal
back to the VAPOR-LOGIC
®
3
controller. The
controller then compares the measured duct RH with
the high limit set point (Duct High Lim RH) that is
entered through the keypad/display in the Set Up
screen. As the measured duct RH approaches the high
limit set point, the system output is proportionally
throttled back. (This scaling of the output starts once
the measured RH is within 6% of the high limit set
point.) Once the measured duct RH drops, full system
output is automatically restored.
Temperature compensation control
With temperature compensation (temp comp) control,
the system is equipped with a window temperature
transmitter. This transmitter sends a signal back to the
VAPOR-LOGIC
3
controller. As the window glass
temperature decreases and approaches the dew point
of the room, the RH set point is automatically
decreased to prevent moisture or ice from forming on
the window. Once the window temperature rises, the
original RH set point is restored. This option is only
available when the system is equipped with an RH
transmitter. It is not available when a remote
humidistat or energy management system is used to
control the humidifier.
Dew point control
Dew point control functions in exactly the same way
as RH control except the dew point is being measured
instead of the RH. The dew point transmitter sends a
signal back to the VAPOR-LOGIC
3
controller. The
user is able to modify the dew point set point and PID
parameters through the keypad/display just as they
could with an RH transmitter.
Operation:
VAV, temp comp, dew point control
VAV, temp comp, dew point control.
Operation
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