Emerson iCOM Temperature Control-Reheat, Glycool Cooling-Free-Cooling, Dual Cooling Source

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Operation

GLYCOOL™ Cooling—Free-Cooling

When GLYCOOL cooling is available, the temperature control will calculate a total cooling require- ment of 200% rather than 100%. Assuming that full GLYCOOL capacity is available, the GLYCOOL valve opens proportionally as the requirement for cooling rises from 0 to 100%. If more than 100% cooling is required, then the compressors are activated at 150% and 200% respectively (133%, 163%, 180% and 200% for a four-step system). If full GLYCOOL capacity is not available, then the GLY- COOL valve will be opened proportionally over a cooling requirement band equal to the available GLYCOOL capacity. The compressors would be activated when the GLYCOOL capacity is exceeded.

For example, if the GLYCOOL capacity is 60%, then the GLYCOOL valve would be full open at 60% cooling requirement and the compressors would activate at 110% and 160% cooling requirement. In order to reduce compressor cycling and prevent hunting, GLYCOOL capacity first becomes available when the entering glycol temperature is at least 8°F (4.4°C) (22% capacity) below the return air tem- perature, or 3°F (1.7°C) below the return air temperature for two hours. GLYCOOL capacity is 100% when the glycol temperature is 25°F (13.9°C) below the return air temperature. The system will con- tinue to operate in Econ-O-Cool mode as necessary as long as the entering glycol temperature remains at least 3°F (1.7°C) (0% capacity) below the return air temperature. If GLYCOOL is not available, the temperature control will operate the compressors in the same manner as a two-step or four-step system without GLYCOOL.

Dual Cooling Source

If dual cooling is available, the sensible cooling system operates in the same manner as a GLYCOOL system, except that it is assumed that 100% chilled water capacity is available any time the chilled water temperature is 3°F (1.7°C) below the return air temperature.

3.5Temperature Control—Reheat

If the room air temperature becomes too cold, the control will call for heating. Heating mode is con- trolled by the Temperature Proportional Band, explained in 3.3.1 - Temperature Proportional Band.

3.5.1Three-Stage Electric, Hot Gas and Hot Water Reheat

The Reheat Proportional Band is divided into three equal parts, each representing one reheat stage. As the Temperature Proportional Band increases the call for heating from 0% to -100%, stages 1 through 3 are switched On, as shown in Figure 19. Your unit will have one of the nine reheat config- uration types shown in Table 4.

Table 4 Reheat configuration types

Type

A

B

C

D

E

F

G

H

I

 

 

 

 

 

 

 

 

 

 

Stage 1

Electric 1

Electric 1

Electric 1

Hot Gas

Hot Gas

Hot Gas

Hot Water

Hot Water

Hot Water

 

 

 

 

 

 

 

 

 

 

Stage 2

-

Electric 2

Electric 2

-

Electric 1

Electric 1

-

Electric 1

Electric 1

 

 

 

 

 

 

 

 

 

 

Stage 3

-

-

Electric 3

-

-

Electric 2

-

-

Electric 2

 

 

 

 

 

 

 

 

 

 

NOTE

1. Hot gas / hot water are not influenced by the setting of electric reheat during dehumidification.

2. Hot gas output will be set only if the selected compressor is in operation.

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Contents Liebert iCOM Page Table of Contents Mounting a Large Display on a Wall Installing a Liebert Icom UNIT-TO-UNITNETWORKTeamwork Figures Tables Large and Small Displays FeaturesESC Icon Key Name Function Keyboard icons and functionsStatus menu, large display, graphical view Accessing Submenus on Small Displays Accessing SubmenusAccessing Submenus on Large Displays Navigating Through the Liebert iCOM MenusMenu tree-Small display, stand-alone or networked Entering a PasswordAdvanced Menu Unit Service Menu UnitStatus Menu System View Status Menu Unit 1 View User Menu Advanced Menu Unit # Service Menu Unit #Viewing Multiple Units with a Networked Large Display SET User menu icons Service menu icons Unit/Fan Control Start Stop Single Unit FunctionsFan Alarm / Fan Protection Settings Loss of Power AlarmVSD Setpoint VSD Fan Speed Setting AutorestartPump Down High Pressure AlarmCompressor Sequencing Digital Scroll High TemperatureCompressor Timing-Units With Two Compressors MBV Operation After Compressor is Turned Off Service Offset-Changing System Pressure SettingsMotorized Ball Valve in Digital Scroll Units Temperature proportional band Temperature Proportional BandCompressor Proportional Bands Compressor ControlOne Single-Step Compressor Without Unloaders-One-Step Two Single-Step Compressors Without Unloaders-Two-StepTwo compressors with unloaders four-step Two Compressors With Unloaders-Four-StepDigital scroll capacity modulation, 10-100% variable Digital Scroll CompressorsDifferential Temperatures / Controls Comparator Circuit Temperature Control-Second Cooling SourceDelta T Temperature Difference Between Room and Glycol Chilled Water ControlSecond cooling source and compressorized cooling Reheat configuration types Temperature Control-ReheatGlycool Cooling-Free-Cooling Dual Cooling SourceHeat On ½ Dead Band 100% Off ½ Proportional Band Decreasing TemperatureSCR Reheat Tight ModeStandard Mode Humidification Humidity ControlHumidification Dehumidification External Humidifier Control-Optional Humidification Infrared HumidifierParameters for infrared humidifier control Dehumidification Dehumidification With Comp settingsDehumidification Low Limit Dehumidification Compressor QuantityReheat During Dehumidification Temperature and Humidity Control TypesControl Types Humidity Sensor Reading Control Types Supply Limit-Optional High and Low, Temperature and Humidity EventsCustomer inputs User Inputs / Customer InputsEnable or Disable Time DelayEvent Types and Properties Event TypesMain FAN Overload Event notifications-large or small display Possible Event NotificationsCalculating Unit Wellness Next Maintenance CalculationCalculation of Next Maintenance and Diagnostics General Maintenance Settings Parameters for Next Maintenance CalculationFans / Heaters / Humidifier Settings and Diagnostics Compressor 1 / 2 Settings and DiagnosticsTeamwork Modes Teamwork ModeApplication of Teamwork Modes No TeamworkTeamwork Mode 1 with two cooling units Standby and Cascade Standby Rotation Typical Standby Lead/Lag FunctionMinimum Network Switch Requirements Placement of Cooling UnitsU2U Hardware Cables and Network Switch Liebert iCOM U2U Ethernet Network Wiring for Unit-to-Unit Communications-U2USample Liebert iCOM network configurations Large Displays Wiring a Liebert iCOM U2U Network Small DisplaysWall-Mount Large Display Combining Large and Small Displays on a U2U NetworkWiring a small display for stand-alone operation Wiring a large display for stand-alone operation Liebert vNSA Ports available for connecting Liebert iCOM control devices298 84mm 305mm 14.25 362mm DPN001136 Rev Mounting Instructions Location ConsiderationsNecessary Mounting Items Liebert iCOM display dimensions Setpoints parameters Spare Part List-Large Display OnlySpare part list parameters-large display only Event log parametersSensor data Set alarms parametersDisplay setup parameters Active AlarmsActive alarms parameters Total run hours parameters Timer parameters-Sleep ModeService contacts parameters Service Menu Parameters Unit diary parameters Unit Diary-Large Display OnlyMaintenance / wellness settings parameters Standby settings / lead-lag parametersWellness COMP2 Wellness HEAT2 Diagnostics / service mode parameters ALM REL 7of Delay Enable Disab Enable Disab Comp 1 Overload Unit X Disconnected WRN Loss of Power LOP MSG, WRN, ALM Call Service MSG, WRN, ALM High Temperature Sensor calibration / setup parameters System / network setup parameters-large display only GBP Network setup parametersStatic RAM Not Available, Invalid, OK HUM Steam Options setup parametersService contact info parameters Service Menu Parameters Service Menu Parameters Page Iti Ne tTi n That
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