Liebert CR020 User manual

Brand: Liebert

Model: CR020

Category: Split-system air conditioners

Type: User manual

This manual is also suitable for

CR035
CR040

Liebert.CRV Series Air Conditioner

User Manual

Version V1.4

Revision date May 28, 2012

BOM 31011886

Emerson Network Power provides customers with technical support. Users may contact

the nearest Emerson local sales office or service center.

Emerson Network Power Co., Ltd.

Address: No.1 Kefa Rd., Science & Industry Park, Nanshan District 518057, Shenzhen

China

Homepage: www.emersonnetworkpower.com.cn

E-mail: [email protected].cn

Important Safety Instructions

Warning

 The manual is retained for the entire service life of the machine.

 The user reads the manually carefully before carrying out any operations on the machine.

 The machine is a piece of professional equipment for use in industry, trades, and other professions, and it is not

intended for sale to the general public.

 The machine is used exclusively for the purpose for which it is intended; incorrect use of the machine 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 restarting, 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:

 The machine restarts automatically.

 The main switch must be opened before opening the internal compartments for any operation.

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

Electrical heaters

Compressor, outlet area and outlet piping (about 100°C)

Components still at low temperature Evaporator

Rotating elements Fan 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

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

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.

Warning -

Risk of refrigerant system rupture or explosion from

overpressurization

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 fieldinstalled 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’.

Digit Nomenclature

The unit is fully defined by twenty-five digits.

1 1 12 3 4 5

6 7 8 9 1011

.. ..

C R 0 2 0

Digit 1 and 2: Family

CR: Liebert.CRV

Digit 3, 4 and 5: Cooling

Capacity "kW" (approx.)

Nominal cooling capacity

Digit 6 - Air Discharge

R: Horizontal airflow

Digit 7 - System Type

A: System Type - Air cooled

W: System Type - Water cooled

C: System Type - Chilled Water

Digit 8 - Airflow

1: Airflow - EC Plug Fan

Digit 9 - Power Supply

0: Power Supply - 380V ~ 415V /3ph/50Hz+N

C: Power Supply - 208V/3ph/60Hz

A: Power Supply - 460V/3ph/60Hz

Digit 10 - Cooling System

2: Cooling System - CW with two way valve

3: Cooling System - CW with three Way

7: Cooling System - DX with digital scroll single

circuit R410A

Digit 11 - Humidification

0: Humidification - None

S: Humidification - Electrode humidifier

Digit 12 – Display

A: Display - Small Display 1 T+H Sensor

N: Display - Small Display 1 Temp Sensor Only

D: Display - Large Display 1 T+H sensor

C: Display - Large Display 1 Temp sensor Only

Digit 13 - Re-Heating

0: None

1: Electric heating 1 Level

Digit 14 - Air Filter

0: G4 (EU4)

1: F5 (EU5)

2: G4 (EU4) + Clogged Filter Alarm

3: F5 (EU5) + Clogged Filter Alarm

8: Merv 8 + Clogged Filter Alarm

9: Merv 11 + Clogged Filter Alarm

Digit 15 - Coil

1: Air cooled - water cooled two ways water valve

7: Water cooled 3 ways water valve

H: CW Standard coil

Digit 16 - Enclosure options

1: Color Standard

2: Color Special

Digit 17 - Condensate pump/crankcase heater

A: DX units - crankcase heater

E: DX units - condensate pump & crankcase heater

L: CW units - no condensate pump

5: CW units - condensate pump

Digit 18 - Option Package

0: None

L: Option Package #1 – humidifier and reheat

lockout & compressor jacket & one additional alarm

H: Option Package - Reheat & Humidifier Lockout

C: Option Package #2 - humidifier and reheat

lockout & one additional alarm

D: Option Package #3 – compressor jacket

Digit 19 - Monitoring

N: Without IS housing

0: With IS housing/no card

1: One IS web card

2: Two IS web cards

3: One IS485 card

4: Two IS485 cards

5: IS web & IS 485 cards

Digit 20 - Sensors

0: Sensors - None

H: Sensors - High Temperature - Firestat

S: Sensors - Smoke Sensor - Smokestat

F: Sensors - Smoke & High Temp - Smoke and

Firestat

Digit 21 - Packaging

P: PLP and pallet Domestic

C: PLP and wooden crate Export

S: Seaworthy

Digit 22 - Special Requirements

A: SFA - none

X: SFA included

Digit 23-25 - Order Identifier

Contents

Chapter 1 Preliminary Operations ....................................................................................................................................... 1

1.1 Inspection ............................................................................................................................................................. 1

1.2 Handling ................................................................................................................................................................ 1

1.3 Operating Limits .................................................................................................................................................... 2

1.4 Noise Level Limits ................................................................................................................................................. 4

1.5 Product Description ............................................................................................................................................... 4

Chapter 2 Unit Positioning ................................................................................................................................................... 8

Chapter 3 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 .................................................................................................................... 14

3.4 Unpacking The Unit ............................................................................................................................................ 14

3.5 Installation ........................................................................................................................................................... 16

Chapter 4 Refrigeration Connections ................................................................................................................................ 19

4.1 Refrigeration Pipeline Connections For Air-Cooled (A) Units .............................................................................. 19

4.1.1 General Layout ........................................................................................................................................ 19

4.1.2 Pipe Diameter And Thickness ................................................................................................................. 20

4.1.3 Installing Pipelines ................................................................................................................................... 21

4.2 Vacuum Creation And Refrigerant Charge ......................................................................................................... 22

4.2.1 R410A Precharge For Air-Cooled (A) Units ............................................................................................. 23

4.2.2 Refrigerant Charge For Air-Cooled (A) Units ........................................................................................... 24

4.3 Refrigeration Circuits .......................................................................................................................................... 24

Chapter 5 Water Connections ........................................................................................................................................... 25

5.1 General Warning ................................................................................................................................................. 25

5.2 Water Connections – Supply Humidifier And Drain Water (All Units) .................................................................. 26

5.3 Chilled Water Connections For Water/Glycol-Cooled (W) Units ......................................................................... 27

5.3.1 Notes For Open Circuit Applications ........................................................................................................ 27

5.3.2 Notes For Closed Circuit Applications ..................................................................................................... 27

5.4 Chilled Water Connections For Chilled Water (C) Units ...................................................................................... 28

Chapter 6 Electrical Connections ...................................................................................................................................... 30

6.1 Cable Entry Ports, Routing Cables And Connection Procedures ........................................................................ 30

6.2 Protective Features Of EC Fans ......................................................................................................................... 31

6.3 Protective Features Of Electrical Heaters ........................................................................................................... 32

6.4 Temperature Probes Placed On Racks .............................................................................................................. 32

Chapter 7 Start-Up ............................................................................................................................................................ 35

7.1 First Start-Up (Or After Long Standstill) .............................................................................................................. 35

7.2 Automatic Restart ............................................................................................................................................... 36

7.3 Checking The Refrigeration Piping Pressure Drops ............................................................................................ 36

7.4 Chilled Water Valve Of Chilled Water (C) Units .................................................................................................. 36

Chapter 8 Operation .......................................................................................................................................................... 38

Chapter 9 Calibrations & Regulation (At Start-Up) ............................................................................................................ 39

9.1 Setting Thermostatic Expansion Valve ............................................................................................................... 39

9.2 Water Leakage Sensor ....................................................................................................................................... 39

9.3 Environment Protection ....................................................................................................................................... 39

Chapter 10 Maintenance & Spare Parts ............................................................................................................................ 40

10.1 Safety Instructions ............................................................................................................................................ 40

10.2 Spare Parts ....................................................................................................................................................... 40

10.3 Maintenance Schedule ..................................................................................................................................... 40

10.4 Air Filter Check Or Substitution ......................................................................................................................... 41

10.5 Condensate Drain And Condensate Pump Systems ........................................................................................ 43

10.5.1 Condensate Drain .................................................................................................................................. 43

10.5.2 Condensate Pump ................................................................................................................................. 43

10.6 Air-Cooled Condenser And Drycoolers ............................................................................................................. 43

10.7 Electrical Heaters .............................................................................................................................................. 43

10.8 Refrigeration Circuit .......................................................................................................................................... 43

10.8.1 Refrigerant Charge Of The Water-Cooled Units .................................................................................... 44

10.8.2 Oil Charge R410A ................................................................................................................................. 44

10.8.3 Oil Topping-Up Of An Installed Circuit ................................................................................................... 44

10.9 Dismantling The Unit ......................................................................................................................................... 44

10.10 Regulation (EC) No. 842/2006 (F-Gas) ........................................................................................................... 45

10.11 Unit Diagnostic ................................................................................................................................................ 46

Appendix 1 Humidair Humidifier ........................................................................................................................................ 47

1. Preface ................................................................................................................................................................. 47

2. Installation ............................................................................................................................................................. 47

3. Humidifier Components ........................................................................................................................................ 49

4. Start-Up And Operation ........................................................................................................................................ 49

4.1 Start-Up ...................................................................................................................................................... 49

4.2 Operation .................................................................................................................................................... 49

5. Maintenance ......................................................................................................................................................... 50

5.1 Removing The Steam Cylinder ................................................................................................................... 50

5.2 Replacing The Steam Cylinder ................................................................................................................... 50

5.3 Annual Maintenance ................................................................................................................................... 50

6. Replacing Humidifier Spare Parts ......................................................................................................................... 51

Appendix 2 Technical Data Tables .................................................................................................................................... 52

Appendix 3 Installation Drawing ........................................................................................................................................ 55

Appendix 4 Refrigerant, Hydraulic And Electrical Connections ......................................................................................... 59

Appendix 5 Refrigeration & Hydraulic Circuits ................................................................................................................... 64

Appendix 6 Wiring Diagram ............................................................................................................................................... 67

Chapter 1 Preliminary Operations 1

Liebert.CRV Series Air Conditioner User Manual

Chapter 1 Preliminary Operations

This chapter introduces the preliminary operations of the Liebert.CRV series air conditioner (Liebert.CRV for short),

including inspection, handling, operating limits, noise level limits and product description.

Warning

- Risk of top-heavy unit falling over

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

Risk of sharp edges, splinters and exposed fasteners. Can cause personal injury. Only trained personnel 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

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 installation plans to verify clearances before moving the unit.

Caution

- Risk of frozen fluids

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 Emerson Corporation or to

your sales representative.

1.2 Handling

Always keep the unit vertically upright and do not leave it out in the open.

 If 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.

 If using a forklift or pallet jack, make sure the forks (if adjustable) are spread to the widest distance that fit under

the skid. Also, ensure the fork length is suitable for the unit length.

 When moving the packaged unit, do not lift it any higher than 152 mm off the ground. Exercise great care if the

unit must be lifted higher than 152 mm; any personnel not directly involved in lifting the unit must be at least 5m

from the unit.

 Take care of the Center of Gravity indicated on the package.

2 Chapter 1 Preliminary Operations

Liebert.CRV Series Air Conditioner User Manual

Table 1-1 Center of gravity

Model

Distance from corner (unit: m)

X (±0.05m) Y (±0.05m) Z (±0.05m)

CR020 0.52 0.30 0.71

CR035 0.50 0.30 0.80

CR040 0.54 0.30 0.80

Note: The center of gravity on the Liebert.CRV varies with the options and the model’s size

Moving by a forklift and unit weight

The schematic diagram of moving the unit by a forklift is shown in Figure 1-1. The unit weight is given in Table 1-2.

Figure 1-1 Moving the unit by a forklift

Table 1-2 Unit weight (unit: kg)

Model Power supply

Weight (±5%)

Air-cooled Water/Glycol-cooled

Chilled water

CR020 380V ~ 415V/3-phase/50Hz 335 350 -

CR035 380V ~ 415V /3-phase/50Hz 365 385 -

CR040 380V ~ 415V /3-phase/50Hz - - 330

Note: Weights of full version units without packaging

1.3 Operating Limits

The units are designed to operate within working ranges (see Table 1-3 ~ Table 1-7). These limits are referred to new

machines or to those that have been correctly installed and serviced.

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.

For all units

Table 1-3 Operating limits for all units

Item From To

Room air

conditions

Temperature 18°C 40°C

Humidity ratio 5.5g/kg 11g/kg

Relative humidity 20% 60%

Storage

conditions

Temperature -20°C 50°C

Power supply

tolerances

Voltage ±10%

Frequency ±2Hz

Chapter 1 Preliminary Operations 3

Liebert.CRV Series Air Conditioner User Manual

For air-cooled (A) units

Table 1-4 Operating limits for air-cooled (A) units

Item Description

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 system 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 (the CRV standard outdoor unit has been configured with the function)

Use Variex fan speed control to regulate the condensing pressure and have a continuous and better

subcooling 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 Emerson 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 manually.

Once the condensing pressure rises at or above the 34bar / 493psi 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

Table 1-5 Relative position of room unit and 50Hz remote condenser

Item Description

From unit to condenser max distance equivalent length

50m

From unit to condenser max geodetic height

-8m ~ 30m

Requirements

Pipe diameter

See Table 4-2

Oil traps on vertical line of gas refrigerant

Install one every 6m

Extra oil charge

See Table 5 and Table 6 in the appendix

Note:

1: If the equivalent length from the indoor unit to the condenser exceeds 50m, please consult with Emerson sales representative;

2: Positive difference in height: condenser above conditioner; Negative difference in height: condenser below conditioner

For water/glycol-cooled (W) units

Table 1-6 Operating limits for water/glycol-cooled (W) units

Item Description

Water or mixture temperature to condenser Min. 5°C

Other information See Chapter 5 Water Conections

For chilled water (C) and water/glycol-cooled (W) units

Table 1-7 Operating limits for chilled water (C) and water/glycol-cooled (W) units

Item

Description

CR020RW CR035RW CR040RC

Max. water pressure (bar) 16 16 16

Max. differential pressure through the

closed valve: Dpcv (kPa)

300 300 175

Max. differential pressure across the

valve for modulating service: Dpms (kPa)

300 300 175

4 Chapter 1 Preliminary Operations

Liebert.CRV Series Air Conditioner User Manual

1.4 Noise Level Limits

The sound pressure level in free field at 1.5m height and 2m in front of the air conditioner, with compressor and fan in

operations, is less than 70dBA for all models (excluding the chilled water unit).

1.5 Product Description

Appearance

The appearance of the air conditioner is shown in Figure 1-2.

Figure 1-2 Appearance of the air conditioner

Example of installation

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.

The example of high density installation with cold aisle and hot aisle alternation is shown in Figure 1-3.

Hot aisle

Cold aisle

Hot aisle

Cold aisle

Hot aisle

Cold aisle

Hot aisle

Cold aisle

Hot aisle

Figure 1-3 Example of high density installation with cold aisle and hot aisle alternation

Chapter 1 Preliminary Operations 5

Liebert.CRV Series Air Conditioner User Manual

Thermal performance

The thermal performance (at 1.1m from floor) of a system with 2 CRV and 20 racks is shown in Figure 1-4.

Figure 1-4 Schematic diagram of thermal performance

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, including 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 panel

The iCOM display panel is shown in Figure 1-5.

Figure 1-5 iCOM display panel

The iCOM display panel shows: air inlet temperature and humidity, air outlet temperature, fans status, cooling power

status, next service time.

Component locations

The component locations of Liebert.CRV air-cooled (A), water/glycol-cooled (W) and chilled water (C) units are

shown in Figure 1-6.

6 Chapter 1 Preliminary Operations

Liebert.CRV Series Air Conditioner User Manual

1. iCOM control display

2. Electric Box 3. Evaporator / CW Coil

4. Condensate pump 5. Electric heaters

6. Humidifier distributor 7. Top water connections

8. Drain tray 9. EC fans

Figure 1-6 Component locations

The component locations of Liebert CR020 ~ CR035 air-cooled (A) units are shown in Figure 1-7.

1. Termostatic expansion valve 2. Solenoid valve 3. Sight glass 4. Filter dryer

5. Liquid receiver 6. Safety valve 7. Humidity/Temp. sensor 8. Humidifier

9. Top refrigerant connections 10. Bottom refrig. connections

Figure 1-7 Component locations of Liebert CR020 ~ CR035 air-cooled (A) units

Chapter 1 Preliminary Operations 7

Liebert.CRV Series Air Conditioner User Manual

The component locations of Liebert CR020 ~ CR035 water/glycol-cooled (W) units are shown in Figure 1-8.

1. Top Water connections 2. Compressor 3. Water condenser

4. Bottom water connections 5. Three-way water valve

Figure 1-8 Component locations of Liebert CR020 ~ CR035 water/glycol-cooled (W) units

The component locations of Liebert CR040 chilled water unit are shown in Figure 1-9.

1. Top CW connections 2. Filters 3. Three-way CW valve 4. Bottom CW connections 5. Humidifier

Figure 1-9 Component locations of Liebert CR040 chilled water unit

8 Chapter 2 Unit Positioning

Liebert.CRV Series Air Conditioner User Manual

Chapter 2 Unit Positioning

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.

For best performances of Liebert.CRV is important to:

 Reduce at minimum recirculation from hot aisle around the ends and/or over the top of the racks, prevent gaps

between the racks.

 Reduce at minimum recirculation from hot aisle through server racks by using blanking panels.

 Ensure cold air is being distributed across the front of all neighboring equipment racks by properly placed

Liebert.CRV unit(s).

 Distribute 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 Emerson 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 server room with different Liebert.CRV position. The CFD

(Computational fluid dynamics) analysis results are shown in Figure 2-1 (height 1.8m off the floor for all following

cases).

Good approach:

Not advised approach:

End of row is preferred.

CRV

Figure 2-1 CFD analysis results of comparing the same server room with different Liebert.CRV position

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 Emerson sales representative.

The CFD analysis result of one Liebert.CRV unit with 2 ~ 6 racks is shown in Figure 2-2.

Chapter 2 Unit Positioning 9

Liebert.CRV Series Air Conditioner User Manual

2 ~ 6 racks (0.6m ~ 5m)

CRV

Figure 2-2 CFD analysis result of one Liebert.CRV unit with 2 ~ 6 racks

3. Placement in the room

1) Width of hot aisle/cold aisle

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.

The width of hot aisle/cold aisle is shown in Figure 2-3.

Min. 0.65m

CRV

0.6m ~ 1.2m

Figure 2-3 Width of hot aisle/cold aisle

The CFD analysis result of cold aisle with different width is shown in Figure 2-4.

Not advised approach:

Good approach:

CRV

< 1.2m

> 1.2m

Note: Please refer to the service area dimensions in Appendix 3.

Figure 2-4 CFD analysis result of cold aisle with different width

10 Chapter 2 Unit Positioning

Liebert.CRV Series Air Conditioner User Manual

2) 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 positions. The CFD analysis result is

shown in Figure 2-5.

CRV

Min. 0.65m Variable

CRV

Example of an application with gaps on both sides

Not advised approach:

Good approach:

Figure 2-5 CFD analysis result of Liebert.CRV unit in different positions

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Liebert CR020 User manual

Brand: Liebert

Model: CR020

Category: Split-system air conditioners

Type: User manual

This manual is also suitable for

CR035
CR040

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Liebert CR020 User manual

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Liebert CR020 User manual

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