Vertiv | Liebert PEX+Chilled Water | User Manual 67
iCOM Controller Operation
• Teamwork Mode 1: Balanced load (small groups of units inside the same environment)
Teamwork Mode 1 works best in small rooms with balanced heat loads. The master unit computes the average
of all cooling units return temperature and humidity sensors’ reading in the operation (fan on) and use it
for controlling. The master unit will send the operating requirements to all operating units according to unit
numbers, rotated by each unit in every 24 hours. 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. Auto set 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 depending upon - how far the system deviates from
the setpoints. 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 o, unit not switched
o, etc.)
Figure 4-10 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 (10% ÷ 50% = 20%).
Figure 4-10 System Proportional Band
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