Operation with Advanced Microprocessor with Graphics Control 21
Auto Restart Delay
This feature allows for the unit to restart automatically after a loss of power. The programmed value
is .1 minute (6 seconds) intervals. A programmed value of zero (0) would require the user to manually
press the ON/OFF switch to start the unit, i.e. no auto restart. The purpose of this feature is to pre-
vent several units from starting at the same time after a loss of power. The message “Restart Delay --
Please Wait” will be displayed when the system is in the auto restart mode. Liebert suggests multiple
unit installations be programmed with different auto restart times.
Dual Cool/Econ-O-Coil Flush
This feature will flush the respective coil for three (3) minutes after the programmed number of hours
of non-use. For example, if the flush time is programmed with 24 hours on a hot water reheat type
system, and heating is not required for a 24 hour period, the hot water valve will be opened for 3 min-
utes to allow the coil to be flushed. The programmed value can be from 0 (no flush) to 99 (99 hours of
non-use).
Display in Degrees
The control can be set to display readings and setpoints in either degrees Fahrenheit (F) or Celsius (C).
Min CW Temp
(Dual cooling units only) This feature permits the user to select the minimum chilled water tempera-
ture that permits simultaneous operation of the chilled water control and compressor control. Below
this minimum chilled water temperature setpoint, the control will operate ONLY the chilled water
control, i.e., the compressor is locked out. Above the minimum chilled water temperature setpoint,
assuming the chilled water temperature is below the return air temperature, the control will operate
the chilled water control and compressor control simultaneously if necessary to satisfy the cooling/
dehumidification requirements.
Default Settings and Ranges
The following table lists the setup functions, their factory default values, and the allowable ranges of
which they can be programmed.
3.7.2 Select Options
The following table is a list of options which should match the options installed with your unit and
should not need to change during normal operation.
3.7.3 Calibrate Sensors
The temperature and humidity sensors can be calibrated by selecting this menu item. “SENSOR”
shows the actual sensor reading or raw reading. “CALIBRATED” shows the sensor reading after the
calibration offset has been added. The temperature sensor can be calibrated ±5 degrees Fahrenheit
and the humidity sensor can be calibrated ±10% RH. When calibrating the humidity sensor, the value
shown will always be % RH, even though absolute humidity control may be selected. If absolute
humidity control is selected, the Normal Status Display will display the adjusted reading and may
not agree with the relative humidity reading displayed while in calibration.
Table 9 Setup functions, default values and ranges
Function Default Range
Cold Start Time Delay* 3 0 to 3 min (0 = no delay)
Restart Time Delay 0.1 0 to 9.9 min (0 = manual restart)
Chilled/Hot Water Coil Flush 24 0 to 99 hrs (also Econ-O-Coil)
F/C Degrees F F or C
Min CW Temp 45 32° to 72°F
*Factory set to 0 for water cooled, glycol, and GLYCOOL units.
Table 10 Unit options
Option Selection
Reheat YES or NO
Humidity YES or NO
Dehumidify YES or NO
Stages of Reheat 2
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