Configuring Low Noise Operation; Liebert Econophase - Emerson Liebert iCOM Manual

U816 Reversal Duration—Selection defines the length of time the fan(s) will be operated in reverse.
This parameter is adjustable from 0-999 seconds. The default set value is 60 seconds.
U817 Reverse Fans Now—Selection performs a rotation when parameter is set to "YES." When
selection is set to "YES," the parameter will automatically change back to "NO" when the timer,
U816, has elapsed. NOTE: If one or both of the compressor(s) is in operation and/or the fan is in a low
noise operation, the request to reverse the fans will be ignored. When the conditions above are met, to
reverse the fans the control will perform a reversal.
U818 Max Speed at OpMode 0 (LN)—Linked to U807 0=LN column and defines the maximum
speed during low noise operation.
U819 Max Speed at OpMode 100 (HE)—Linked to U807 100=HE column and defines the
maximum speed during normal or high efficiency operation.
U820 Current Max Speed—Parameter shows the status of the actual maximum fan speed.
3.8.5

Configuring Low Noise Operation

First, determine the days and time of day low noise is required. This will be set U806 through U808
respectively. Second, determine the maximum fan speed setting during low noise operation.
In this example, the user does not want fan speed to exceed 35% max speed from 10 p.m. to 8 a.m.
weekdays.
1. Set U805 Mon. - Fri. columns to "yes"
2. Set U806 interval time from 22:00 to 8:00
3. U807 = 0% / 100%
4. U818 = 35% (Max fan speed low noise)
5. U819 = 100% (Max fan speed during normal operation)
The settings above result in a 35% maximum speed when the timer is active (i.e., at night) and will
operate the fan between 0 and 100% maximum speed of when the timer is inactive (normal operation,
during daytime).
3.8.6

Liebert EconoPhase

The Liebert EconoPhase is a option that can be added to the Liebert DSE. The Liebert EconoPhase is
a pumped refrigerant circuit that bypasses the Liebert DSE's compressors and provides energy
efficient cooling when the outdoor ambient is low.
The Liebert EconoPhase, when combined with the Liebert DSE and Liebert MC, has seven operating
modes:
• Idling with Compressor and Pumps Off
• Startup
• Compressor Operation
• Compressor to Pump Changeover
• Pump Operation
• Pump to Compressor Changeover
• Mixed Mode
The compressor and pump operation modes represent the majority of the run time of the system.
These modes both remove heat from the space and reject the heat out of the space through the
Liebert MC. The flow paths during each mode of operation are detailed with the images below.
The Liebert EconoPhase system currently activates when the outdoor temperature is lower than 35°F
and will operate in either Pump Mode or in Compressor Mode. When the Liebert EconoPhase is
active, the Liebert DSE will control the pump(s) speed based on the indoor room conditions. The
Liebert EconoPhase is also equipped with one discharge pump valve per circuit that maintains the
pressure across the variable speed pump to prevent cavitation.
The Liebert EconoPhase continues to operate until the unit can no longer maintain temperature
control, which is determined by the proportional band. That means that small proportional bands
may lead to a reduction of economization hours.
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Operation
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Liebert iCOM for Liebert DSE
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