Data Aire dap4 touch, User Manual

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101
Operation of Dehumidification
To remove humidity, the cooling coil must operate below the dewpoint temperature.
Consequently, as the temperature drops reheat (if enabled) may stage on. Please
see the operation of reheat section for more information.
Humidity Anticipation: When this feature is enabled (set in the factory menu), the
Humidity set point is 1% for every 1.5° that the return air temperature is
from the set point to a maximum 10° offset.
Fan Speed Assist: When this function is enabled in the factory menu, the fan
speed will be reduced (by 5 to 20%) during the dehumidification mode (CW or DX
units). The lower fan speed helps to condense the humidity in the air.
Note: This
feature requires a discharge air temperature sensor to be installed.
Safeties Dehumidification will not run under the following conditions: Air Flow
Alarm, Floor Water alarm, Condensation Alarm or a Dehumidification Inhibit
command (from BMS).
Timed Safeties: Dehumidification mode cannot run within 5 minutes of a
humidification cycle.
Temperature Safeties: When Dehumidification mode is set to an
“In Limit” mode
it will stop if the temperature drops 2°F below the set point minus the dead band.
Operation will resume when the temperature rises back to the set point.
Dehumidification - Chilled Water
The method of CW valve modulation depends which type of humidity control
(selected in the factory menu) is selected:
Relative Humidity Control: When the humidity rises above the humidity Setpoint
+ Deadband the valve will open 100%. It will return to cooling modulation when
humidity drops to the humidity Setpoint.
Dewpoint Humidity Control: In addition to the relative humidity control list above,
The CW valve will also open 100% when the dewpoint rises above the High
Dewpoint setpoint.
Energy Saver: While in dehum mode, DX assistance is delayed by the DX Assist
Delay setting on the CW PID screen (default is 2 mins).