Emerson Liebert CRV User manual

Liebert®CRV
10-50 kW
A/W/C, 50 Hz Versions
Precision Cooling
For Business- Critical ContinuityTM
English Cod. 273870 Rev. 11.10.2013
Refrigerant
R410A
Use
proper
tools
USER MANUAL

1
IMPORTANT SAFETY INSTRUCTIONS
SAVE THESE INSTRUCTIONS
CAUTION
SThe manual is retained for the entire service life of the machine;
SThe user reads the manually carefully before carrying out any operations on the machine;
SThe control is used exclusively for the purpose for which it is intended; incorrect use of the
control shall release the manufacturer any liability.
This manual has been prepared to enable the end-user to carry out only the operation that can
be made with the panels closed. Any operation that require the opening of doors or equipment
panels must be carried out only by qualified personnel.
Each machine is equipped with an Electric Insulation device which allows the operator to work
in condition of safety. Switch off the machine with this electric insulation device before any
maintenance operation to eliminate risks remaining (electric shocks, burns, automatic restart-
ing, moving parts and remote control).
The panel key supplied with the unit must be kept by person responsible for maintenance.
For identification of the unit (model and serial no.) in case of the necessity for assistance or
spare parts, locate the identification label on the outside of the unit.
Potential hazards
The protective covers can be removed only after the electric power has been cut off by opening
the main switch.
A warning label on the front and back panels reminds that:
Sthe machine restarts automatically,
Sthe main switch must be opened before opening the internal compartments for any opera-
tion.
If the doors are opened immediately after the machine has been switched off, there might be
some hazard related to:
components still at
high temperature
Selectrical heaters
Scompressor , outlet area and outlet piping (about 100°C)
components still at low
temperature Sevaporator
rotating elements Sfan impellers, they might continue to rotate for a while by
inertia
These residual risks are highlighted by warning labels on the machine
WARNING
Risk of electric shock. Can cause injury or death.
Disconnect local and remote power supplies before working within.
Before proceeding with installation, read all instructions, verify that all the parts are included
and check the nameplate to be sure the voltage matches available utility power.
The iCOM microprocessor does not isolate power from the unit, even in the “unit off” mode.
Some internal components require and receive power even during the “unit off” mode of iCOM
control.
The factory-supplied optional disconnect switch is inside the unit. The line side of this switch
contains live high-voltage.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote
disconnect switch. Refer to unit electrical schematic.
Follow all local codes.
WARNING
Risk of explosive discharge from high-pressure refrigerant. Can cause injury or death.
This unit contains fluids and gases under high pressure. Relieve pressure before working with
piping.

2
WARNING
Risk of refrigerant system rupture or explosion from overpressurization. Can cause equipment
damage, injury or death.
If a pressure relief device is not provided with the condenser unit, the system installer must
provide and install a discharge pressure relief valve rated for a maximum of 609 psig (42bar) in
the high side refrigerant circuit. Do not install a shutoff valve between the compressor and the
field installed relief valve.
One or more additional pressure relief valves are required downstream of any and all fieldin-
stalled isolation. Do not isolate any refrigerant circuits from overpressurization protection.
For systems requiring EU CE compliance (50Hz), the pressure relief valve must be CE certified
to the EU Pressure Equipment Directive by an EU “Notified Body.”

12 3
45 6
78 9
10 11
12 13
14
15
16
17
18
19 20
21 22
23
24
25
26
27
MODEL AND SERIAL NO.
DATA PLATE
FRONT VIEW
32
30
28
31
29
ELECTRICAL PANEL
3
Attention: data relevant to the
supplied unit are indicated on the inboard
label (see below empty fax-simile).
Data in the manual are referred to stan-
dard conditions and can be modified wi-
thout any advance notice.
Data plate fac-simile for 50 Hz units,
CE marked
POS. DESCRIPTION
1Compressor Full Load Ampere [A]
2Compressor Locked Rotor Ampere [A]
3Compressor quantity
4Evaporator fan Full Load Ampere [A]
5Evaporator fan Locked Rotor Ampere [A]
6Evaporator fan quantity
7Condenser fan Full Load Ampere [A]
8Condenser fan Locked Rotor Ampere [A]
9Condenser fan quantity
10 Electrical heating Ampere
11 Electrical heating steps
12 Humidifier Ampere
13 Steam production capacity
14 Max. unit AC Ampere
15 Max. unit DC Ampere
16 Rated peak withstand current
17 Rated short-time current
18 Refrigerant type
19 High pressure switch Stop
20 High pressure switch Restart
21 Low pressure switch Stop
22 Low pressure switch Restart
23 Min. room operation temperature
24 Max. room operation temperature
25 Min. room operation humidity
26 Max. room operation humidity
27 Max. refrigeration circuit pressure, gauge
28 Manufacturing plant
29 Manufacturing date
30 Model
31 Serial number
32 Power input

4
1 432 710
98 25....11
Digit 1 and 2
Family
CR Liebert CRV
6
Digit Nomenclature
The unit is fully defined by twenty-five digits.
5
Digit 3, 4 and 5
Size: Cooling Capacity “kW” (approx.)
Nominal Cooling Capacity
CR010
Digit 6 - Air Discharge
RAir Discharge Horizontal airflow
Digit 7 - System Type
ASystem Type air cooled
WSystem Type water cooled
CSystem Type Chilled Water
Digit 8 - Airflow
1Airflow - EC Plug Fan
Digit 9 - Power Supply
0Power Supply 400V / 3ph / 50Hz+N
Digit 10 - Cooling System
2Cooling Systems - CW with two way Valve
3Cooling Systems - CW with Three Way
7Cooling Systems - DX Digital scroll with TXV
DCooling Systems - DX Digital scroll with EEV
Digit 11 - Humidification
0Humidification - none
SHumidification - electrode humidifier
Digit 12 -Display
0iCOM without Display Temperature Control
1iCOM without Display Temperature and Humidity
Control
ADisplay - Small Display 1 T+H Sensor
NDisplay - Small Display 1 Temp Sensor Only
DDisplay - Large Display 1 T +H sensor
CDisplay - Large Display 1 Temp sensor Only
Digit 13 -Re-Heating
0Re-heating - none
1Re-heating - electric heating 1 Level
Digit 14 - Air Filter
0Air Filter - G4 (EU4)
1Air Filter - F 5 (EU5)
2Air Filter - G4 (EU4) + Clogged Filter Alarm
3Air Filter - F 5 (EU5) + Clogged Filter Alarm
8Air Filter - Merv 8 + Clogged Filter Alarm
9Air Filter - Merv 11 + Clogged Filter Alarm
Digit 15 - Coil
1Coil - Air cooled - water cooled two ways water valve
7Coil - water cooled 3 ways water valve
HCoil - CW Standard coil
Digit 16 - Enclosure options
1Enclosure - Color Standard
2Enclosure - Color Special
Digit 17 -Condensate pump
LNo condensate pump
5Condensate pump
Digit 18 - Option Package
0Option Package None
LOption Package #1 – humidifier and reheat lockout &
compressor jacket & one additional alarm
COption Package #2 - humidifier and reheat lockout &
one additional alarm
DOption Package #3 – compressor jacket
Digit 19 - Monitoring
NWithout IS housing
0With IS housing / no card
1One IS web card
2Two IS web cards
3One IS485 card
4Two IS485 cards
5IS web & IS 485 cards
Digit 20 - Sensors
0Sensors - None
HSensors - High Temperature - Firestat
SSensors - Smoke Sensor - Smokestat
FSensors - Smoke & High Temp - Smoke and Firestat
Digit 21 - Packaging
PPackaging - PLP and pallet Domestic
CPackaging - PLP and wooden crate Export
SPackaging - seaworthy
Digit 22 - Special Requirements
ASFA - none
XSFA included
Digit 23-25 -Order Identifier

i
INDEX
IMPORTANT SAFETY INSTRUCTIONS 1..........................................................
SAVE THESE INSTRUCTIONS 1..................................................................
1.0 Preliminary Operations 1..................................................................
1.1 Inspection 1........................................................................................
1.2 Handling 1.........................................................................................
1.3 Operating limits 2....................................................................................
1.4 Noise level limits 3...................................................................................
1.5 Product Description 4................................................................................
2.0 Positioning -- unit placement 8............................................................
3.0 UNPACKING AND Installation 13...........................................................
3.1 Reference guide for receiving, unpacking, and preparing for installation. 13...................................
3.1.1 Equipment Inspection 13.............................................................................
3.1.2 Packing Material 13..................................................................................
3.2 Recommended Unit Handling Equipment 13.............................................................
3.3 Handling the Unit While Packaged 13...................................................................
3.4 Unpacking the Unit 14................................................................................
3.5 Removing the Unit from the Pallet using Piano Jacks 14...................................................
3.6 Removal of Piano Jacks 16............................................................................
3.7 Installation 17.......................................................................................
4.0 Refrigeration Connections 20..............................................................
4.1 Refrigeration pipeline connections Air --- cooled (A) units 20................................................
4.1.1 General layout (Tab. b) 20.............................................................................
4.1.2 Pipe diameter and thickness 21........................................................................
4.1.3 Installing pipelines 21................................................................................
4.2 Vacuum creation and refrigerant charge 23..............................................................
4.2.1 R410A precharge Air --- cooled (A) units 24..............................................................
4.2.2 Refrigerant charge Air --- cooled (A) units 24.............................................................
4.3 Refrigeration circuits 24...............................................................................
5.0 Water Connections 25.....................................................................
5.1 General warnings 25.................................................................................
5.2 Water connections – supply humidifier and drain water (all units) 25.........................................
5.3 Chilled water connections Water/Glycol --- cooled (W) units 26.............................................
5.3.1 Notes for open circuit applications 27...................................................................
5.3.2 Notes for closed circuit applications 27..................................................................
5.4 Chilled water connections Chilled water (C) units - (Fig. k) 27...............................................
6.0 Electrical Connections 29.................................................................
6.1 Electrical connections 29.............................................................................
6.2 Protective features of EC fan 30.......................................................................
6.3 Protective features of Electrical Heaters 30...............................................................
6.4 Temperature probes placed on racks 30.................................................................
7.0 Start-- up 34..............................................................................
7.1 First start---up (or after long standstill) 34................................................................
7.2 Automatic restart 35..................................................................................
7.3 Checking the refrigeration piping pressure drops 35......................................................
7.4 Chilled water valve Chilled water (C) units 35.............................................................
8.0 Operation 36.............................................................................
9.0 Calibrations & Regulation (at start -- up) 37..................................................
9.1 Setting the thermostatic expansion valve 37.............................................................
9.2 Water leakage sensor (Liquistat) 37.....................................................................
9.3 Environment protection 37............................................................................

ii
10.0 Maintenance / Spare Parts 38..............................................................
10.1 Safety instructions 38................................................................................
10.2 Spare parts 38......................................................................................
10.3 Maintenance schedule 38.............................................................................
10.4 Air filter check or substitution 39.......................................................................
10.5 Condensate Drain and Condensate Pump Systems 40....................................................
10.5.1 Condensate Drain 40.................................................................................
10.5.2 Condensate Pump 40................................................................................
10.6 Air-Cooled Condenser and Drycoolers 40...............................................................
10.7 Electrical Heaters 40.................................................................................
10.8 Refrigeration circuit 41................................................................................
10.8.1 Refrigerant charge of the water---cooled units 41..........................................................
10.8.2 Oil charge R410A 41.................................................................................
10.8.3 Oil topping --- up of an installed circuit 42.................................................................
10.9 Dismantling the unit 42...............................................................................
10.10 Regulation (EC) no. 842/2006 (F --- gas) 42...............................................................
10.11 Unit diagnostic 44...................................................................................
Appendix
Humidair Humidifier A --- 1.......................................................
Technical data Table B --- 1.......................................................
Installation Drawing C --- 1.......................................................
Refrigerant, Hydraulic and Electrical Connections D --- 1...........................
Refrigeration & Hydraulic Circuits E --- 1..........................................

x
y
z
Preliminary Operations
1
PreliminaryOperations
1.0 PRELIMINARY OPERATIONS
WARNING!
Risk of top-heavy unit falling over. Can cause death, injury and equipment damage. Read all of the
following instructions before attempting to move, lift or remove packaging from the unit.
CAUTION!
Risk of sharp edges, splinters and exposed fasteners. Can cause personal injury. Only trained per
sonnel wearing appropriate safety headgear, gloves, shoes and glasses should attempt to move, lift
or remove packaging from the unit or prepare the unit for installation.
CAUTION!
Risk of overhead interference. Can damage the unit and structure. The unit may be too tall to fit
through a doorway while on the skid. Measure the unit and doorway heights and refer to the in
stallation plans to verify clearances before moving the unit.
CAUTION!
Risk of frozen fluids. Can cause equipment damage. Keep the unit upright, indoors and protected
from dampness, freezing temperatures and contact damage.
1.1 Inspection
Upon arrival of the unit, and before unpacking it, verify that the delivered equipment matches the
bill of lading. Examine the packaging for any signs of mishandling or damage. Inspect all items for
damage, visible or concealed. Report any damage immediately to the carrier and file a damage
claim. Send a copy to Liebert Corporation or to your sales representative.
1.2 Handling
SAlways keep the unit vertically upright and do not leave it out
in the open.
SIf possible, transport the Liebert CRV using a forklift or pallet
jack. Otherwise use a crane with belts or cables and spreader
bars to protect the unit’s sides from damage.
SIf using a forklift or pallet jack, make sure the forks (if ad
justable) are spread to the widest distance that fit under the
skid. Also, ensure the fork length is suitable for the unit
length.
SWhen moving the packaged unit, do not lift it any higher than
51-102 mm off the ground. Exercise great care if the unit
must be lifted higher than 102 mm; any personnel not dir
ectly involved in lifting the unit must be at least 5 m from the
unit.
STake care of the Center of Gravity indicated on the package
CENTER OF GRAVITY
DISTANCES FROM CORNER X
± 0.05 m
Y
± 0.05 m
Z
± 0.10 m
010 0.54 0.30 0.75
020 0.52 0.30 0.71
035 0.50 0.30 0.80
040 0.54 0.30 0.80
050 0.54 0.30 0.80
The center of gravity on the Liebert CRV varies with the options and the model’s size.

Preliminary Operations
2
Fig. a - Unit handling
weight ± 5%
[kg]
Air-cooled Water/Glycol-cooled
010 400/3/50 280 290
020 400/3/50 335 350
035 400/3/50 365 385
Chilled water
040 400/3/50 330
050 400/3/50 365
Weights of full version units without packaging
1.3 Operating limits
The units are designed to operate within working ranges (see Tab. a).
These limits are referred to new machines or to those that have been correctly installed and ser
viced.
The warranty clauses are no longer valid for any possible damage or malfunction that may occur
during or due to operation outside the application values.
Tab. a - Operating limits
For all units (*)
From: To
Room air conditions
Temperature 18°C40°C,
Humidity ratio 5.5 g/kg 11 g/kg
Relative humidity 20 % 60%
Storage conditions Temperature - 20°C50°C
Power supply tolerances
V ± 10%
Hz ± 2
(*) For chilled water unit CR050RC:
This unit is not allowed to run with dehumidification.
The room conditions, the inlet water temperature and the fan speed shall be managed to avoid
latent capacity.

Preliminary Operations
3
For Air - cooled (A) units
Outdoor temperature: lower limit
20°C
To install an air conditioner in places in which external temperature reaches very low values sometime in the
year requires some means of control to maintain adequate condensing pressures to ensure proper liquid sys
tem operation.
With low temperatures the refrigerant condensates in pipeline and the liquid tends to fulfill the condenser.
It's mandatory to install the following components:
1. NON RETURN VALVE (liquid line)
Install a non- return valve in the liquid line directly out of the condenser. It doesn’t allow the liquid to come
back to the condenser (that means efficiency loss and dangerous stress for the compressor).
2. VARIEX FAN SPEED CONTROL
Use Variex fan speed control to regulate the condensing pressure and have a continuous and better subcool
ing control.
It’s suggested to have:
3. HORIZONTAL CONDENSER POSITION
The condenser horizontal disposition (vertical flow) is necessary to reduce subcooling variations due to direct
wind exposure. (very important to have a good subcooling control).
For all exceptions contact the Liebert Sales Representative.
Outdoor temperature: higher limit
This limit is determined by coupled condenser model. Exceeding of this limit (or a lack of maintenance), will
caused a compressor stop by HP safety thermostat. Reset to normal operation can only be carried out manu
ally.
Once the condensing pressure rises at or above the 34 bar value, the capacity of the compressor is reduced
by 20% compared to the requested capacity. This because iCOM control tries to maintain the unit's operability
reducing the cooling power of digital scroll.
Remote Condenser
To ensure correct operation, best performance, and longest life the units must be connected to remote
condensers approved by Emerson Network Power.
The warranty clauses are no longer valid if unit is connected to a not approved remote condenser.
Relative position room unit vs. 50 Hz remote condenser
From unit to condenser max distance equivalent length, m (1) 50
From unit to condenser max geodetic height, m (1) (2) Max above 30 Max below 8
Requirements
Pipe diameter (1) see Tab. c
Oil traps on vertical line of gas refrigerant, m every 6
Extra oil charge see Technical data table - Tab. 4
For lenght higher than 30m condenser oversized +15%.
(1) For more details see Chapter 4 - Refrigeration connections.
(2) Positive difference in height: condenser above conditioner. Negative difference in height: condenser below conditioner
For Water/Glycol - cooled (W) units
Water or mixture temperature to condenser, lower limit (other information Chap. 5) min. 5°C
For Chilled water (C) and Water/Glycol - cooled (W) units
Max. water pressure 16 bar
Max. differential pressure through the closed valve: Dpcv
Max. differential pressure across the valve for modulating service: Dpms
Models Dpcv (kPa) Dpms (kPa)
CR010RW 300 300
CR020RW 300 300
CR035RW 300 300
CR040RC 175 175
CR050RC 175 175
1.4 Noise level limits
The sound pressure level in free field at 1.5 m height and 2 m in front of the air conditioner, with
compressor and fan in operations, is less than 70 dBA for all models.

Preliminary Operations
4
1.5 Product Description
Unit with
iCOM Display Unit without iCOM Display
The Liebert CRV is a range of full-featured compressorized (air, water, glycol cooled) and chilled
water cooling units to be installed within a row of high density computing racks in a “hot-aisle-cold-
aisle“ configuration.
Fig. b - Example of high density installation with cold aisle and hot aisle alternation
CR
CR
CR
CR
CR CR
CR
CR
Hot aisle
Cold aisle
Hot aisle
Hot aisle
Cold aisle
Fig. c - Thermal performance (at 1.1m / 43 inch from floor) of a system with 2 CRV and 20 racks.

1
2
3
4
8
6
5
9
7
Preliminary Operations
5
Inlet air enters this unit from the hot aisle, is filtered, cooled and conditioned, and is returned to
the cold aisle. It provides all the necessary functions of a standard precision air conditioner, includ-
ing cooling, heating, humidification, dehumidification, air filtration, condensate management,
temperature control, alarm functions and data communications. The Liebert CRV is optimized for
maximum cooling capacity in minimal footprint.
iCOM display, if available, shows: air inlet temperature and humidity; air outlet temperature; fans
status; cooling power status; next service time.
Fig. d - Component location Liebert CRV Air-cooled (A), Water/Glycol-cooled (W), Chilled water (C)
units
1iCOM Control
Display
2Electric Box
3Evaporator coil /
CW coil
4Condensate
Pump
5Electric heaters
6Humidifier dis-
tributor
7Top water
connections
8Drain tray
9EC fans

8
110
3
4
7
9
È
ÈÈ
ÈÈ
ÈÈ
ÈÈ
È
È
È
ÈÈ
ÈÈ
È
È
ÈÈ
È
ÈÈ
È
2
5
6
Unit with 1 fan Unit with 2 fans
2
3
1
4
5
È
È
È
È
È
È
È
È
È
È
È
È
È
È
È
È
È
Unit with 1 fan Unit with 2 fans
Preliminary Operations
6
Fig. e - Component location Liebert CR010-020-035 Air - cooled (A) units
1Termostatic ex
pansion valve
2Solenoid valve
3Sight glass
4Filter dryer
5Liquid receiver
6Safety valve
7Humidity/Temp.
sensor
8Humidifier
9Top refrigerant
connections
10 Bottom refrig.
connections
Fig. f - Component location Liebert CR010-020-035 Water/Glycol - cooled (W) units
1Top Water
connections
2Compressor
3Water
condenser
4Bottom Water
connections
53 ways water
valve

2
3
1
5
4
Unit with 3 fans Unit with 2 fans
Preliminary Operations
7
Fig. g - Component location Liebert CR040-050 Chilled water unit
1Top CW
connections
2Filters
3Three way CW
valve
4Bottom CW
connections
5Humidifier

Positioning - unit placement
8
Posi tioning - uni t placem ent
2.0 POSITIONING - UNIT PLACEMENT
This chapter provides some ideas of typical installation of the Liebert CRV unit(s), shows several
examples of the server room layouts and applications using Liebert CRV units.
In order to eliminate the transmission of vibrations, avoid any contacts between Liebert CRV unit
and the racks of the server room.
If coverage (e.g. “Smart Aisle™”) is installed, avoid its contemporary contact with both, racks and
CRV.
For best performances of Liebert CRV is important to:
Sreduce at minimum recirculation from hot aisle around the ends and/or over the top of the
racks, prevent gaps between the racks
Sreduce at minimum recirculation from hot aisle through server racks by using blanking pan-
els
Sensure cold air is being distributed across the front of all neighboring equipment racks by
properly placed
Liebert CRV unit(s)
Sdistribute load within the rack – it is generally advised to distribute the load as much possible
uniformly across the rack height, except for the rack closest to the Liebert CRV unit, where
it is suggested to have the higher density load in the bottom and central part of the rack
For more details refer to following details or contact Liebert Sales Representative.
1. Placement in the row of racks
For single row application with one Liebert CRV unit it is not preferred to put the unit in
the middle of the row because of possible hot spots at top part of racks, unless in
combination with CoolFlex or in application with more Liebert CRV units.
The best approach is to place the Liebert CRV at the end of the row, resulting into much
better air distribution. Please refer to the sample case study comparing the same
serveroom with different Liebert CRV position.
The CFD (Computational fluid dynamics) analysis results are shown in height 1.8m off
the floor (for all following cases).
C
R
V
Good approach:
C
R
V
Not advised approach:

C
R
V
min 0.65 m *
0.6-1.2 m *
Good approach:
C
R
V
0.6-1.2 m *
For good air distribution it is recommended to
keep width of the cold aisle as small as possible
for single row server room. Otherwise the cold
air discharged by Liebert CRV unit is being led
far from server suction and hot air may by-
passed from hot aisle.
Exceptions where wider cold aisle may be used
are: applications with CoolFlex (Cold Aisle
Containment) or with two rows facing each
other.
For width of the hot aisle there are no prefer
ences, there is just minimum requirement
needed for enough for service area*.
C
R
V
C
R
V
< 1.2 m
Not advised approach:
C
R
V
C
R
V
> 1.2 m
Note:
* Please refer also to Service area dimensions Fig. 1. - Enclosure C
Positioning - unit placement
9
2. Number of racks / length of the row
Standard application with one Liebert CRV unit is with 2-6 racks. The exact number of
racks depends on size of Liebert CRV unit used and heat load per rack. Whenever
applying more than 6 racks for one CRV or Heat load more than 10kW per rack contact
Liebert sales representative
C
R
V
2-6 racks (0.6-5 m)
3. Placement in the room
3.a. Width of Hot / Cold aisle

Positioning - unit placement
10
3.b. Distance between the ends of rows and walls
For single row application with one Liebert CRV unit it is not preferred to put the unit at
wall because of not proper air paths and possible hot spots at furthest racks, unless in
combination with CoolFlex (cold aisle containment) or in application with more Liebert
CRV units.
The best approach is to keep a gap between at least 0.65m or to use more Liebert CRV
units. Good approach is also having wall at the furthest rack.
Please refer to the following sample case study comparing various Liebert CRV posi
tions
C
R
V
min 0.65 m * Variable
Example of an application with gaps on both sides
Good approach:
Not advised approach:
C
R
V
C
R
V
As you can see on CFD result above, it is not advised to place Liebert CRV at the wall in single row layout.
On the contrary, it is not an issue in application with two rows and two or more Liebert CRV units.
Good approach:
C
R
V
C
R
V
Note:
* Please refer also to Service area dimensions Fig. 1. - Appendix C
0.6 - 1.8 m
min 0.1 m *

Positioning - unit placement
11
4. Solutions with redundancy
Following an example of more complex applications where N+1 redundancy provided.
Please note the number and size of Liebert CRV units have to be designed in order to achieve
required cooling capacity if any of the units fails. The other option to easily achieve redundancy
is CoolFlex (Cold aisle containment), see point 5 below.
Example of an application with one row and N+1 redundancy (right
side unit failed).
C
R
V
Example of an application with two rows and N+1 redundancy (unit
placed right down failed).
C
R
V
C
R
V
O
F
F

Positioning - unit placement
12
5. Example of applications with CoolFlex
When high density IT equipment is used (typically over 10kW per rack) or load distribution in
the row(s) of racks is not constant and high energy efficiency is required it is strongly recom
mended to apply CoolFlex (cold aisle containment) together with Liebert CRV.
Other advantage of the CoolFlex application is less limitations, see above points.
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C
R
V
C
R
V
Knürr CoolFlex
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C
R
V
Knürr CoolFlex
6. Example of applications with Liebert XD
When high density IT equipment is used (typically over 10kW per rack) with less floor space
available especially when scalable solution is required (starting from less heat load and ready
for future grown), the best answer is Liebert CRV together with Liebert XD system.
Please find following an example layout of typical installation with two rows of racks with
Liebert
XDV modules. Two Liebert CRV units are used to support the Liebert XD system and to ensure
N+1 redundancy on humidity control. See also CFD result showing site view of the room.
C
R
V
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ÌÌ
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ÌÌÌ
ÌÌÌ
XDV XDV
ÌÌ
ÌÌ
ÌÌ
ÌÌ
ÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
ÌÌÌ
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