Liebert Challenger Plus CP20A U Instruction manual

Technical Data
Manual
Keeping Business in Business
LiebertLPN: SLE CP TDM E.1
HPN: 272030 (17/6/99)
Challenger
Plus

Table of Contents
Nomenclature 1
Introduction 2
Standard features - all models6
Standard features - DX models9
Standard features - chilled water models12
Optional features - all models13
Air cooled data18
Water cooled data20
Air cooled dual source data22
Water cooled dual source data24
Freecooling data26
Chilled water cooled data28
Condenser matching tables30
Chilled water data - all models31
Electrical data - all models32
Sound data - all models37
Technical data - optional components39
Dimensional data - all models47

Nomenclature
System nomenclature
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Challenger Plus - Technical Data Manual
20DAAir Distribution:
D = Downflow
U = Upflow
System type:
A = Air Cooled
W = Water/ Glycol Cooled
F = Freecooling
D = Dual Source Air Cooled
H = Dual Source Water Cooled
C = Chilled Water Cooled
Model Number:
Nominal capacity in kW at 24 0 C, 50% RH
Liebert Challenger Plus Unit
The range of models is as follows:
Air Cooled
Single CircuitCP20A U/DCP24A U/DCP28A U/DCP34A U/DCP40A U/D
Dual CircuitCP26A U/DCP32A U/DCP42A U/DCP46A U/D
Water /Glycol Cooled
Single Circuit CP20W U/DCP24W U/DCP28W U/DCP34W U/DCP40W U/D
Dual CircuitCP26W U/DCP32W U/DCP42W U/DCP46W U/D
Freecooling
Single Circuit CP20F U/DCP24F U/DCP28F U/DCP34F U/DCP40F U/D
Dual CircuitCP26F U/DCP32F U/DCP42F U/DCP46F U/D
Dual Source Air Cooled
Single Circuit CP20D U/DCP24D U/DCP28D U/DCP34D U/DCP40D U/D
Dual CircuitCP26D U/DCP32D U/DCP42D U/DCP46D U/D
Dual Source Water Cooled
Single CircuitCP20H U/DCP24H U/DCP28H U/DCP34H U/DCP40H U/D
Dual CircuitCP26H U/DCP32H U/DCP42H U/DCP46H U/D
Chilled Water Cooled
Single Circuit CP25C U/DCP35C U/DCP50C U/DCP60C U/DCP70C U/D
CP

Introduction
Precision environmental control may be defined as the
simultaneous control of air temperature, humidity,
distribution and cleanliness on a continual, around-the-clock
basis.
Conventional building or ‘comfort’ systems, as they are
called, are not designed for this 24-hour, year-round usage;
theylacktheabilityto provide theprecision and reliabilityor
‘close control‘ that is so critical to many applications.
The Liebert Challenger Plus is a new series of air
conditioners designed by Liebert to meet the requirementsof
data processing centers and other small and medium sized
critical areas.
The Challenger Plus series comprises both direct expansion
units and chilled water units. Cooling capacities range from
20 to 70 kW, for a total of 54 models. Direct expansion units
are equipped with compliant scroll compressors. The design
of the scroll compressor, ensures a constant refrigerant
pressure,thusimprovingreliability,energyconsumptionand
sound emission.
Liebert technology and energy
efficiency
Liebert has become a world leader in precision
environmental control systems by providing maximum
energy efficiency without compromising precision and
reliability.
Liebert takes a no-compromise approach to environmental
control system design. All enhancements to energy
efficiency are designed to reduce operating time of key
components. This is accomplished by taking advantage of
alternate sources of cooling when available or, by reducing
compressorwork loadwhenthe heatloadin thecriticalspace
is lower.
Applications
The Challenger Plus unit is ideally suited for precision close
control of the following types of environment:
•Data processing centers
•Telecommunications
•Industrial applications
Thedesignof theChallengerPlusunit can varydependingon
theapplication,consulttheLiebertApplicationsEngineering
Department for specific details.
Manufacture
All units are built in accordance European directives
98/37/CE (89/392/CEE; 91/368/CEE; 93/68/CEE),
89/336/CEE; 73/23/CEE. The Liebert Air Conditioning
QualitySystemis approvedbyLRQA inaccordancewith the
standards UNI EN ISO 9001: 1994.
Each unit is supplied complete with a Test Certificate and
Declaration of Conformity.
All Challenger Plus units carry the “CE” mark and fully
comply with European Directives concerning mechanical,
electrical and electromagnetic safety.
Features
•Newfan section-singleinlet,radialcentrifugalfans(plug
fans) with backward curved blades. Variable speed motor
withexternal rotor. Availablestatic pressure upto 350 Pa,
standard configuration
•High COP (Co-efficient Of Performance)
•High SHR (Sensible Heat Ratio)
•Low energy consumption; High EER (Energy Efficiency
Ratio)
•Low operating cost
•All materials used in the unit are fully recyclable
•Low internal air-side pressure drop
•High efficiency filtration, up to EU8 available
•Modular construction
•Sandwich construction of panels with non-flammable -
Class 0 (ISO 1182.2) insulation
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Introduction (continued)
System types
Air cooled units
Air cooled models consist of an evaporator coil, a compliant
scroll compressor, high and low pressure switches, an
externally equalised, adjustable, thermostatic expansion
valve, service ports, refrigerant line sight glass, liquid
receiver with pressure-relief valve and filter drier. The units
are shipped with a holding charge of dry Nitrogen.
Models CP20A, CP24A, CP28A, CP34A and CP40A are
single circuit. Models CP26A, CP32A, CP42A and CP46A
are dual circuit.
Air cooled units require matched air cooled condensers. Fan
speed controlled condensers are available from Liebert for a
full range of outside ambient temperatures. Refer to the
Condensers Technical Data Manual (P/N SLE CD TDM) for
full details.
Water/Glycol cooled units
Water/Glycol cooledmodels consist of an evaporator coil,a
compliant scroll compressor, high and low pressure
switches, an externally equalised, adjustable, thermostatic
expansion valve, service ports, refrigerant line sight glass,
filter drier, stainless-steel plate heat exchanger and a
head-pressure control valve (water regulating valve).
Pressure relief valves are fitted downstream of the plate heat
exchanger.The refrigerant circuits are precharged with
refrigerant in the factory.
Models CP20W, CP24W, CP28W, CP34W, CP40W are
singlecircuit.ModelsCP26W,CP32W,CP42WandCP46W
are dual circuit.
The units operate with mains water, cooling tower water or
water in a closed circuit with an external drycooler.
When operating in a closed circuit, it may be necessary
(depending on outside temperatures) to add monoethylene
glycoltoprevent thewaterfreezinginwinter,refer tothe unit
Installation Manual for applicable percentages.
A pump is used to circulate water (water/glycol) through the
unit (not supplied as standard).
Ifmainswaterortowerwaterisused,itisrecommendedtofit
a mechanical filter on the water line to protect the plate heat
exchanger against possible impurities contained in the water
(for plate heat exchanger cleaning, refer to the Installation
Manual).
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Challenger Plus - Technical Data Manual
Figure 1 - Air Cooled Downflow UnitFigure 2 - Water/Glycol Cooled Upflow Unit

Introduction (continued)
Freecooling units
Freecooling models consist of an evaporator coil, a
compliant scroll compressor, high and low pressure
switches, an externally equalised, adjustable, thermostatic
expansion valve, service ports, refrigerant line sight glass,
filter drier, stainless-steel plate heat exchanger, a
head-pressure control valve (water regulating valve), a
2-way modulating valve and a freecooling coil.Pressure
relief valves are fitted downstream of the plate heat
exchanger.The refrigerant circuits are precharged with
refrigerant in the factory.
Models CP20F, CP24F, CP28F, CP34F, CP40F are single
circuit. Models CP26F, CP32F, CP42F and CP46F are dual
circuit.
The units operate with water in a closed circuit from an
external drycooler.
When operating in a closed circuit, it may be necessary
(depending on outside temperatures) to add monoethylene
glycoltoprevent thewaterfreezinginwinter, refertothe unit
Installation Manual for applicable percentages.
A pump is used to circulate water (water/glycol) through the
unit (not supplied as standard).
Operation
Freecooling units have two modes of operation, depending
on the outside temperature.
In normal operation, the unit cools the air in the conditioned
space using the compressor and refrigerant coil (direct
expansion).
When outside temperatures are low enough, water from the
external drycooler is used to cool the air in the conditioned
spacedirectly usingthe Freecooling coil.This temperatureis
the ZET or Zero Energy Temperature.
Dual source air cooled
Dual Source Air Cooled models consist of an evaporator
coil, a compliant scroll compressor, high and low pressure
switches, an externally equalised, adjustable, thermostatic
expansion valve, service ports, refrigerant line sight glass,
liquid receiver with pressure-relief valve, filter drier, 3-way
motorised modulating valve and a chilled water coil. The
units are shipped with a holding charge of dry Nitrogen.
Models CP20D, CP24D, CP28D, CP34D and CP40D are
single circuit. Models CP26D, CP32D, CP42D and CP46D
are dual circuit.
Air cooled units require matched air cooled condensers. Fan
speed controlled condensers are available from Liebert for a
full range of outside ambient temperatures. Refer to the
Condensers Technical Data Manual (P/N SLE CD TDM) for
full details.
Operation
In normal operation, when the temperature of the second
sourceislowenough,thechilledwatercoilis usedtocoolthe
air in the conditioned space. If the temperature of the chilled
water rises above the temperature required to maintain the
load, chilled water cooling is stopped and the compressor is
started. The load is then maintained using dx cooling.
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Challenger Plus - Technical Data Manual
Figure 3 - Freecooling Upflow UnitFigure 4 - Dual Source Air Cooled Downflow Unit

Introduction (continued)
Dual source water/glycol cooled
Dual Source Water/Glycol cooled models consist of an
evaporator coil, a compliant scroll compressor, high and low
pressure switches, an externally equalised, adjustable,
thermostatic expansion valve, service ports, refrigerant line
sight glass, filter drier, stainless-steel plate heat exchanger, a
head-pressure control valve (water regulating valve), a
3-way motorised modulating valve and a chilled water coil.
Pressure relief valves are fitted downstream of the plate heat
exchanger.The refrigerant circuits are precharged with
refrigerant in the factory.
Models CP20H, CP24H, CP28H, CP34H, CP40H are single
circuit.Models CP26H,CP32H, CP42Hand CP46H aredual
circuit.
Normal Operation
In normal operation, when the temperature of the second
sourceislowenough,thechilledwatercoilis usedtocoolthe
air in the conditioned space. If the temperature of the chilled
water rises above the temperature required to maintain the
load, chilled water cooling is stopped and the compressor is
started. The load is then maintained using dx cooling.
DX Operation
The units operate with mains water, cooling tower water or
water in a closed circuit with an external drycooler.
When operating in a closed circuit, it may be necessary
(depending on outside temperatures) to add monoethylene
glycoltoprevent thewaterfreezinginwinter,refer tothe unit
Installation Manual for applicable percentages.
A pump is used to circulate water (water/glycol) through the
unit (not supplied as standard).
Ifmainswaterortowerwaterisused,itisrecommendedtofit
a mechanical filter on the water line to protect the plate heat
exchanger against possible impurities contained in the water
(for plate heat exchanger cleaning, refer to the Installation
Manual).
Chilled water cooled
Chilled water models incorporate a chilled water coil with a
three-way modulating motorised chilled water valve and
insulated piping.
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Challenger Plus - Technical Data Manual
Figure 5 - Dual Source Water Cooled Upflow Unit Figure 6 - Chilled Water Cooled Downflow Unit

Standard features - all systems
Access/Maintenance
Routine maintenance access to refrigerant circuit
components, compressor, liquid receiver, thermal expansion
valve, sight glass, filter dryer etc. is available through the
frontpanel of theunit. Serviceaccess to theair filter, thefan,
humidifier,electric panel, electronic controller PCB,electric
reheats etc. is also through the unit front panel.
Customer connections to the refrigerant circuit (hot gas and
liquid line), cooling water circuits, mains power input
supply, humidifier water supply and condensate drain lines
are located in the base of the unit.
The compressor is housed in a separate airtight compartment
within the unit, allowing access to the compressor while the
unit is in operation.
Cabinet and panels
The cabinet is manufactured from zintec, painted with
epoxy-polyester powder paint and assembled using stainless
steel screws.
The front and rear panels are double-skinned, with 22mm
fiberglass insulation sandwiched between the panels to
reduce noise emission and heat loss. The side panels, which
are isolated from the inside of the unit, are lined with 22mm
fiberglass insulation sealed in an aluminum foil.
Theedgesofthepanels arefittedwithseals topreventairloss
and to keep noise levels to an absolute minimum.
The structure is fully in compliance with Class 0 (ISO
1182.2). All surfaces in contact with the air flow are
washable in order to reduce the formation of bacteria. All
materials used are CFC-free and may be recycled.
Air distribution
All units in the range are available in three configurations,
Downflow, Upflow Front Return and Upflow Bottom
Return, refer to Figure 7.
Fan section
The unit is fitted with a direct-drive, single inlet backward
curved, galvanized painted steel radial centrifugal fan (plug
fan). The fan motor is a three-phase, 25-speed motor (speed
is adjustable via an autotransformer). The motor is rated to
IP44 and complete with internal thermal protection.
The fan impeller is statically and dynamically balanced and
equipped with self-lubricating bearings. The fan is mounted
on vibration-absorbing rubber supports to reduce vibration
transmission between the fan and the unit frame. This
vibration attenuation helps to keep noise emission to a
minimum. The motor is capable of providing the rated
airflow at external static pressures of up to 350 Pa.
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Figure 7 - Air Distribution
Figure 8 - Autotransformer and Fan