Operating instructions

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