Emerson Liebert DS Precision Cooling System 28-105kW Manuel D’Utilisation
Operation
19
DT between Room Air / Outdoor—Sets the delta that must be achieved between the outdoor
temperature and either the return setpoint or return actual reading to enable the Liebert Air
Economizer.
DT between Room / FC Type—Determines the method to activate the water circuit on dual-cool
DT between Room / FC Type—Determines the method to activate the water circuit on dual-cool
and free-cool units. When this parameter is set to “Contact,” a dry contact closure can be used to
activate the free cooling circuit. When this parameter is set to “Value,” the delta between the water
temperature of the free-cooling circuit and the actual room temperature are compared.
DT between Room Air / FC Fluid—Sets the delta between the actual room temperature and the
DT between Room Air / FC Fluid—Sets the delta between the actual room temperature and the
free-cooling fluid temperature to determine if cooling can be provided.
Minimum CW Temp—Enables the temperature at which free-cooling can operate independently
Minimum CW Temp—Enables the temperature at which free-cooling can operate independently
without assistance of the compressor circuit.
Minimum CW Temp Value—Sets the water temperature at which 100% free-cooling can be
Minimum CW Temp Value—Sets the water temperature at which 100% free-cooling can be
provided to handle the full room load. When the fluid temperature is below this setting then the
compressors will no longer turn on until the water temperature is above the minimum CW Temp.
Lockout FC at FC Fluid below—The temperature that turns off the free-cooling circuit when the
Lockout FC at FC Fluid below—The temperature that turns off the free-cooling circuit when the
water temperature is too low. This setting prevents frost from building up on the free-cooling pipes
when the outdoor ambient is extremely low.
Transition Change—Applied over the “Cooling Filter at 0% / 100%” when the cooling signal makes
Transition Change—Applied over the “Cooling Filter at 0% / 100%” when the cooling signal makes
the transition between cooling and dehumidification. This will smooth the cooling capacity changes
between dehumidification and cooling.
Figure 11 Service/Economizer, page 1 of 3
Enable Economizer—Sets the Liebert Air Economizer operation to one of the following modes.
These selections only determine if the Liebert Air Economizer is available for use; they do not
determine or override damper position. Damper position is always controlled by the sensor set to
control temperature (i.e., Return / Supply Sensor)
• Yes: This parameter will operate the Liebert Air Economizer based on the outdoor sensor reading
and will allow the Liebert iCOM to determine if the conditions are within the acceptable range of
operation.
• NO: This parameter will disable the Liebert Air Economizer and will not allow Liebert Air Econo-
mizer to operate even if the outdoor conditions are acceptable.
• Remote: This parameter will enable the Liebert Air Economizer and ignore the outdoor Liebert
iCOM sensor even if the conditions are outside the range of operation.
Economizer (page 1 of 3)
to change parameter
to confirm
to select parameter
for next/previous unit
then
then
UNIT 01
SA01
SA02
SA03
SA04
SA05
SA06
SA07
SA08
SA09
SA10
SA11
SA02
SA03
SA04
SA05
SA06
SA07
SA08
SA09
SA10
SA11
PASSWORD (Actual Level 3)
????
Enable Economizer
Yes, No, Remote
Status
Min
Act Max
Humidity Ratio
OK/NOK
5.7
8.0 11.0
Wet Bulb Temp
OK/NOK
55°F
Outdoor Temp
OK/NOK
73°F
Stop ECO at Setpoint +
25°F
Economizer Mode
ON/OFF
Dewpoint (Calculated)
48°F
Economizer Override At 102°F
Delay After Fan Start
Delay After Fan Start
5 min