Operation Of Fan - Data Aire dap4 User Manual

Operation of Fan

When the system is turned on, the fan(s) will start running and must run for a full
minute before any temperature or humidity control functions will begin.
Note on minidap4: The fan can be set to "Automatic" mode. This allows to fan to
turn off until there is a need for temperature or humidity control.
Fan Speed:
Modulation of plug fan speed is based on the CW and DX mode selection. (Note:
selections are limited based on the unit model).
Constant Speed: Fan runs at a constant speed setting and is not
modulated.
BMS Speed*: Fan begins at the constant speed setting then modulates
according to a BMS value.
Vlv Pos Speed: Fan modulates based on the position of the CW valve.
Air Pressure: Fan modulates to maintain the static air pressure set point.
Const Flow: Fan modulates to maintain the airflow set point.
BMS Flow: Fan modulates to maintain the airflow of the BMS.
Vlv Pos Flow: Fan modulates to maintain the airflow based on CW valve
position.
Return Air T.: Fan modulates to return air temperature to maintain temp set
point.
Mod to Rack: Fan modulates to rack temperature to maintain temperature
set point.
Mod to Comp: Fan modulates to variable compressor speed.
Mod to deltaT: (Shown only on IRDX model). Fan will modulate to the
difference between return and discharge temperature to maintain the delta
temperature set point.
Note: Except for the selections of Constant Speed and Mod to Comp
optional sensors are required.
Safeties: Fan modulation will be forced to maximum speed due to the following
conditions: Humidifier On, Heater On, Energy Saver and Compressor On, Low
Discharge Temp alarm, High or Low Return Temp alarm, Freeze Temp alarm,
Rack Temp error (only if Fan set to modulate to Comp) or a Floor Water alarm.
On CW units, the fan will be forced to 100% due to a fan overload alarm so that
other fans (if any) can make up for the one that shut-down.
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