Teamwork Mode 1 - Emerson Liebert CRV User Manual

12.4.3 Teamwork Mode 1

Teamwork Mode 1 works best in small rooms with balanced heat loads. The return temperature and
humidity sensor readings of all units in operation (fan On) are averaged by the master unit and
displays this information in the System View. Control can be based on either the maximum or
average temperature readings of the connected units in the group. If set to control off an average, the
number of units calculated in the average can be set lower than the total number of units connected.
This provides a more defined control strategy, by taking into account only the worst case readings.
The master unit will send the operating requirements to all operating units according to unit
numbers.
In this teamwork mode, most of the parameters are shared; if set in any one of the units, all other
units will follow with the same settings. AutoSet will adjust the proportional band in Teamwork
Mode 1.
The master unit evenly divides the system proportional band among the number of available units.
Each unit will receive instruction on how to operate from the master unit based on how far the system
deviates from the setpoints. Fans, compressors, and chilled water valves will operate in parallel as
temperature deviates from set point. See Figure 121 and paragraphs below for more information.
The number of available units is calculated like:
• In non-standby configuration: all units with fan On
• In typical standby function (no cascade): all units with fan On
• In cascade mode: all units that could operate (no alarm, which forces the unit to switch Off, unit
not switched Off, etc.)
NOTE
Low limit and reheat during dehumidification are managed from each unit independently.
Figure 121 shows how two cooling units work together in Teamwork Mode 1. Since Unit 1 and Unit 2
are available to operate, the master unit, Unit 1, averages the temperature and humidity sensor
readings from each unit.
The master unit determines that a 60% call for cooling is required for the system. Since there are two
available cooling units, each unit makes up half of the system proportional band; Unit 1 handles
0-50% system call for cooling and Unit 2 handles 51-100%. For every 1% system call for cooling, each
unit provides 2% of its total cooling capacity.
The 60% system call for cooling exceeds the 50% Unit 1 can provide, so Unit 1 operates at full
capacity. The remaining 10% system call for cooling (60% - 50% = 10%) is handled by Unit 2. Unit 2
responds by operating at 20% cooling capacity (50% ÷ 10% = 20%).
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Liebert CRV 136
Operation in Teamwork Mode