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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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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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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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

Standard features - all systems (continued)
Filtration
The air filter is made of synthetic fiber cells in a cardboard
frameandis designedtominimise theairpressure dropwhile
maintaining maximum filter efficiency. It is easily
accessed/replaced by opening the front doors of the unit.
The guaranteed efficiency is EU4 (Eurovent EU4/5, 30%
efficiency), (G4, CEN standard). Optional filtration levels to
EU8 (G8) are available on request.
Prefilters are available on upflow models.
Electrical panel
Theelectricpanel, locatedatthefront oftheunitin anairtight
compartment, contains the MCB’s, contactors, transformer,
controller PCB and overload relays etc. Each high voltage
system component is provided with a separate overcurrent
protective device. All high-voltage components are touch
protected by means of a plastic cover. The electric panel
complies with the EN 60204-1.
All units are designed for operation at 400V/3ph/50 Hz ( +
10%) and are fitted with a mains disconnect switch.
Microprocessor controller -
Microface
The Microface environmental control system is
microprocessor based and can be programmed to match the
uniqueneeds ofanyapplication. Theprocessor integratesthe
separate mechanical and electrical components into a
‘state-of-the-art’ conditioned space support system that
controlsandmonitors temperature,humidity, airflowand air
cleanliness.
The controlsystem offers atailored and well proven advance
in reliability and control flexibility allowing the unit to
modifyitsperformanceinresponsetochangingcriticalspace
conditions.
The controller allows local monitoring and programming of
the following room conditions:
Temperature (o C)
Temperature setpoint (5.0o C – 40.0o C in steps of 0.1
o
C)
Temperature sensitivity (1.0o C - 10o C in steps of 0.1 oC)
Humidity (%RH)
Humidity setpoint (20%RH - 80%RH in steps of 1%)
Humidity sensitivity (5%RH - 20%RH in steps of 1%)
The parameters are enunciated using symbols and text on an
LCD display. Normal operating modes are indicated by
symbols on the display. Alarm conditions activate a visual
indicator.
The following alarms are standard:
•High temperature
•Low temperature
•Fan failure
•High pressure alarm – (compressorised systems only)
•Low pressure alarm - (compressorised systems only)
•Electrical reheat high temperature
•Memory failure
•Common alarm
Other alarms are also available when the relevant option is
ordered with the unit (e.g. if a humidifier is ordered with the
unit, the High Humidity, Low Humidity etc. alarms are
enabled).For a fulllist of allthe options andalarms available
with the Microface controller, refer to the Microface
Controller Operation Manual (P/N SLE MF OM).
The controller also incorporates a sequential auto-restart
timer, allowing field adjustable time delays to be applied to
unitrestartafterapowerloss(orothershutdown). Thetimers
allow multiple units to be restarted while limiting
instantaneous inrush current.
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Standard features - all systems (continued)
Electric reheat
The three-stage reheat is of rigid design for extended
operational life. The reheat has ample capacity to maintain
room dry-bulb conditions during a system call for
dehumidification. The low-watt density, electrically
enclosedelementsaremadeofaluminumsurroundedbyhigh
efficiency fins, reducing sheath temperatures and
eliminating ionisation. The reheat is phase-balanced.
Reheatcontrol isof theON-OFFtype. Thereheat isprovided
with a manual reset, reheat safety thermostat, to disable the
reheat in the event of high temperature.
The reheat safety stat. also incorporates a magneto-thermal
switch which protects the reheat from short circuits, should
the harness be damaged accidentally.
Electric reheat can be combined with hot gas or hot water
reheat activated in different stages.
Refer to the Technical Data Tables for reheat capacities,
FLA’s etc.
Humidifier
The unit is fitted with an electronic steam bottle humidifier
suitable for use with water of varying degrees of hardness,
provided that the water is not treated or demineralized. The
humidifier iscompletewithawaterinletvalve,awateroutlet
valve and a maximum water level sensor.
The steam cylinder is installed in the unit’s airtight
compartment to avoid heat losses. Steam from the cylinderis
mixed with the discharge air from the evaporating coil by
means of a copper steam distributor.
The unit controller monitors the condition of the steam
cylinder, and generates an alarm when the cylinder needs to
be changed. Cylinder replacement is easy and quick.
The humidifier is complete with a self-adapting flow control
system which monitors water conductivity and controls the
electrical current passing through the cylinder. Output
adjustment is from 30 - 100% via the unit controller.
Humidification control may be of the proportional or of the
on-offtype, according tothe requirements ofthe installation:
On-off control is set as standard.
RefertotheOptionalsectionoftheTechnical DataTablesfor
humidifier capacities, FLA’s, etc.
Dehumidification
On air-cooled models, the unit dehumidifies the air by
reducing the airflow across the coil (the fan is switched to a
lower speed) and switching on the compressor.
In chilled water models, the unit dehumidifies by fully
opening the chilled water valve.
In Dual Source units, the unit dehumidifies using the
"Current"coolingsource.Ifthecurrentsourceis DX, theunit
dehumidifies the air by reducing the airflow across the coil
(the fan is switched to a lower speed) and switching on the
compressor.If the current source is chilled water, the unit
dehumidifies by fully opening the chilled water valve.
In Freecooling units, the unit disables freecooling on a call
for dehumidification and dehumidifies the air by reducing
the airflow across the coil (the fan is switched to a lower
speed) and switching on the compressor.
Packaging
As standard, the units are wrapped in bubble-wrap to protect
painted surfaces, enclosed in a cardboard box and mounted
on a wooden pallet.
On request, for sea transport etc., the units can be packed in
wooden crates or cases complete with silicon desiccant.
Warranty clauses
The warranty does not cover any damage or malfunction of
the unit which may occur during or as a result of operating
the unit outside of the specified application limits.
Liebert does not accept responsibility for any damage caused
by improper use of the product.
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Standard features - DX systems (continued)
Refrigerant circuit
Units are available as single and dual circuit. The circuit(s)
consist of a compressor, a thermal expansion valve, a liquid
line sight glass, a filter dryer, an evaporator coil, a liquid
receiver (air cooled only) and high and low pressure
switches.
For safety reasons, (especially during machine start-up), it is
recommended to install a non-return valve(s) (supplied as an
option, on request) on the liquid line from the condenser, to
protect the compressor from unexpected refrigerant
migrations. All low temperature parts of the refrigerant
circuit are insulated as standard.
Evaporator
The evaporator coils are designed to provide maximum coil
area for more precise control of temperature and humidity.
With this computer designed coil arrangement, low velocity
air passes through the coil providing the most effective
surface exposure with less turbulence and greater efficiency
in the cooling and dehumidification processes. The coil is
designed for the high sensible heat ratio required by critical
spaces. The coil is tested to 30 Bar.
The evaporator coil is made of copper tubes with treated
aluminum fins (to withstand corrosive atmospheres). A
corrosion resistant drain pan is provided with the coil on all
models.
Compressors
The fully hermetic compliant scroll compressor incorporates
several safety features for protection during normal and the
occasional abnormal operating conditions. They are:
•Self resetting overloads to sense excessive currents and
temperatures.
•An internal pressure relief valve which limits discharge
pressure to protect mechanical parts.
•Motor insulation that is resistant to chemical attack.
•Rubbermountingto ensurereducedcompressor noise and
vibration.
•IP54 protection
Schraeder connections are fitted to the unit for service
access.
Refrigerant
R22 HCFC is the standard refrigerant used in the Challenger
Plus range. An optional “Green” refrigerant, R407C is also
available. In this case the compressor is supplied with ester
oil. Air cooled units are shipped with a nitrogen holding
charge, water, dual source water and freecooling units are
charged with refrigerant in the factory.
Sight glass
Refrigerantlinesightglassesserveasameansofquickvisual
inspection to determine if there is moisture in the system and
if the system is properly charged.
Filter-dryer
Liquid line filter-dryers ensure a clean, moisture-free
refrigerant system for extended component life. The filter
drieris suitable foruse withstandard R22 andoptional “Zero
ODP” refrigerant R407C.
Expansion valve
The externally equalised, adjustable,thermostatic expansion
valve smoothly controls refrigerant flow during varying
indoor heat loads and outdoor ambient temperatures by
controlling evaporator superheat.
Safety controls
Eachcompressor hasa manual-resethigh pressureswitch for
high pressure protection and a high pressure alarm circuit to
warn of high system pressures, allowing corrective action to
be taken before a significant loss of temperature control
occurs.
The low pressure switch is auto-resetting and detects low
pressure conditions such as loss of refrigerant charge. The
pressure switch calibration values are shown in the
Installation, Operation & Maintenance Manual supplied
with the machine.
Crankcase heaters
Crankcase heaters are supplied with all compressorised
models. They maintain minimum refrigerant temperature
and are energised while the unit is powered and the
compressor is off.
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Figure 9 - Scroll Compressor

Standard features - DX models (continued)
Air cooled only
Liquid receiver
A welded steel liquid receiver is provided to maintain
constant and even refrigerant flow to the expansion valve, in
allcircumstances.Shut-offvalvesareinstalledasstandardon
theinletandoutlet ofthereceivertoassistmaintenance ofthe
circuit, if required.
Asuitablyratedpressurerelief valveisinstalledontheliquid
receiver.Thevalveisequippedwithathreaded connectionto
allow the refrigerant to be discharged outside of the
conditioned space.
Air cooled condenser
A matching Liebert air cooled condenser with fan speed
control should be ordered with the unit. Details of the
condensers are provided in this manual, full details of all
condensers for all outdoor ambients are available in the
Condenser Technical Data Manual, (P/N SLE CD TDM).
Note:The suggested condenser selections/performances for
each outdoor ambient are based on calculated data. The
actual selection of a condenser should always be verified on
the basis of the specific working conditions on each site.
Water cooled/freecooling units only
Plate heat exchanger
All water cooled units (models W, H, F) are fitted with a
brazed plate heat exchangers made of stainless steel. This
type of condenser is designed for high efficiency heat
exchange. The condenser is intentionally oversized for the
application to reduce pressure drops (and the energy
consumptionofthecirculationpump)inthewatersupplyand
thusallow the unit to operate with anexternal water cooler in
a closed circuit at high outdoor temperatures. Pressure relief
valves are fitted downstream of the condenser. The valve is
equipped with a threaded connection to allow therefrigerant
to be discharged outside of the conditioned space.
Water cooled units can operate with mains water, cooling
tower water or water in a closed circuit with an external
drycooler. Freecooling units operate with water in a closed
circuit from an external drycooler only.
When operating in a closed circuit, it may be necessary
(depending on outside temperatures) to add monoethylene
glycoltopreventthewaterfreezinginwinter,refertotheunit
Installation Manual for applicable percentages.
A pump is used to circulate water (water/glycol) through the
unit (it is not supplied).
Ifmainswaterortower waterisused, itisrecommended tofit
a mechanical filter on the water line to protect the condenser
against possible impurities contained in the water (for
condenser cleaning, refer to the Installation Manual).
Drycooler
A drycooler can be supplied, if required. Full details of all
drycoolers are available in the Drycooler Technical Data
Manual, P/N SLE DC TDM.
Head pressure control valve
Head pressure operated regulating valves accurately control
the condensing temperature and system capacity for various
entering fluid temperatures. A 2-way head pressure control
valveisfittedasstandardonwater/glycolcooled,dualsource
water cooled and freecooling units.
The valve controlsthe condensing pressure by regulatingthe
water flow to the plate condenser. It is installed at the
condenser outlet with the pressure probe positioned on the
refrigerantdischargeline. Itisautomaticallyclosed whenthe
compressor is not operating. It is sized for inlet water flow
temperatures lower than 170C resulting in low water-side
pressure drops.
For higher water inlet temperatures, higher water flowrates
are required and possibly special water regulating valves,
consult Liebert Applications Engineers for details.
Freecooling only
Freecooling coil
The Freecooling coil is located on the return air side of the
evaporatorcoil.Water/glycol flowtothe coiliscontrolled by
a pre-piped 2-way modulating motorised valve. When
supplied with a coolant solution of sufficiently low
temperature, the coil is sufficiently sized to offer an equal
cooling capacity to that obtained using the refrigeration
circuit. The coil is tested to 30 Bar.
2-way control valve
As the outdoor ambient drops to a sufficiently low
temperature, the 2-way motorised valve modulates the flow
tothe coil,asin achilledwater system.The valveincludesan
operating linkage and electric motor.
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Standard features - DX models (continued)
Dual source only
Dual source units consist of the standard direct expansion
refrigeration circuit and an additional cooling coil with a
three-way motorised modulating valve.
The additional coil is located on the return air side of the
evaporator coil. Flow to the coil is controlled by a pre-piped
3-way equal percentage motorised valve.
Thenormalcontrolstrategy oftheunit istouse thesecondary
source(chiller supply,processwater supplyetc.) to maintain
the room load until a sensor detectsthat the secondary source
is no longer at the required temperature. Direct expansion
cooling is then switched on and maintains the load.
Operating limits (DX models)
Challenger Plus direct expansion units are designed for
operation within the following working limits (the limits are
applicable to newly commissioned machines which have
been correctly installed and maintained).
Indoor operating range
All models from 18.0°C, 45% R.H. to 27.0°C, 55% R.H.
To minimise the possibility of water carry over, (i.e. too
much condensate on the evaporator coil leading to the
formation of water droplets), it is critical to ensure that the
latent load (difference between total and sensible load) does
not exceed 5.5 kW.
Outdoor operating range(Air cooled - A, D)
Lower limit
-20°C with fan speed control installed in the condenser.
Upper limit
This is determined by the capacity of the condenser coupled
to the unit (at the relevant outdoor ambient). If the limit is
exceeded,the High PressureSwitch will shutthe compressor
down. The switch must then be manually reset after the
problem has been rectified.
Condenser installation
Condenser above indoor unit
Maximum distance between indoor unit and external air
condenser: 30 meters equivalent length.
Condenser below indoor unit
Maximum geodetic height difference between condenser
and unit: 3 meters.
Air flow
The minimum and maximum air flows and available
External Static Pressure are given in the Technical Data
section of this manual. The fan motor thermal overload
protects the unit from any damage which could result from
operating outside the specified values.
Voltage tolerance
All models 400 V ±10%
Frequency tolerance
50 Hz ± 2 Hz.
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Figure 10 - Head Pressure Control Valve

Standard features - chilled water models
Cooling coil
The large face area/low face velocity, deep wave fin coil
allows precise control of temperature and humidity during
cooling and dehumidification, and is designed to optimize
fluid velocity and minimize pressure drop. The full face area
is active during cooling and dehumidification, resulting in
operational energy saving in the application area. A
corrosion resistant drain pan is provided on all models. The
coil is tested to 30 Bar.
3-way control valve
Themotorised chilled watervalve provides equalpercentage
control action in response to room temperature and humidity
as sensed by the microprocessor. This results in a
proportional ratio of capacity to stem travel. The valve
includes an operating linkage and electric motor. The valve
can be manually adjusted to the closed position (on the
coil-side of the valve) using the tool provided.
Operating limits
Challenger Plus chilled water units are designed for
operation within the following working limits (the limits are
applicable to newly commissioned machines which have
been correctly installed and maintained).
Indoor operating range
All models from 18.0°C, 45% R.H. to 27.0°C, 55% R.H.
To minimise the possibility of water carry over, (i.e. too
much condensate on the evaporator coil leading to the
formation of water droplets), it is critical to ensure that the
latent load (difference between total and sensible load) does
not exceed 5.5 kW
Air flow
The minimum and maximum air flows and available
External Static Pressure are given in the Technical Data
section of this manual. The fan motor thermal overload
protects the unit from any damage which could result from
operating outside the specified values.
Voltage tolerance
All models 400 V ±10%
Frequency tolerance
50 Hz ± 2 Hz.
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Figure 11 - Equal Percentage Valve Characteristic

Optional features - all models
Hot gas reheat
Challenger Plus can be supplied with a hot gas reheat coil if
required. This type of reheat uses the heat which is normally
rejected in the condenser to heat the air in the conditioned
space, thus saving energy. A control valve prevents the
refrigerant from flowing to the reheating coil when reheat is
not required. The reheat coil is single or double row
depending on the model, and constructed of copper tubes
with aluminum fins.
Whenhotgasreheatisrequested,itissuppliedinconjunction
with electrical reheat in two stages as follows:
Stage 1: Hot gas reheat
Stage 2: Hot gas reheat + electrical reheat
Note: The capacity of the electrical reheat in stage 2 is equal
to two thirds of the total capacity of the standard electrical
reheat for a given model.
RefertotheOptionalsectionoftheTechnical DataTablesfor
reheat capacities etc.
Hot water reheat
The economical hot water reheats are controlled by a 3-way
(on/off) valve from the microprocessor control panel. The
system is completely pre-piped and includes an air bleed
valve. The reheat coil is single or double row depending on
the model, and constructed of copper tubes with aluminum
fins. The coil is tested to a pressure of 30 bar.
A hot water thermostat (provided by the customer) is used in
the valve control sequence to determine the availability of
reheat capacity.
When hot water reheat is requested, it is supplied in
conjunction with electrical reheat in two stages as follows:
Stage 1: Hot water reheat
Stage 2: Hot water reheat + electrical reheat
Note: The capacity of the electrical reheat in stage 2 is equal
to two thirds of the total capacity of the standard electrical
reheat for a given model.
RefertotheOptionalsectionoftheTechnical DataTablesfor
reheat capacities etc.
Non-return valves (models A and D)
Refrigerant non-return valves for air-cooled units are
available as an option.
The valve is installed on the liquid line, close to the
condenser and mounted vertically.
Liebert recommend that the valve be installed when the total
system charge exceeds the specified values given in the
Optional section of the Technical Data Tables.
High efficiency filters
EU5 filters
Optional100mmEU5 highefficiencyfiltersare availablefor
all models. The high efficiency filters are interchangeable
with the standard filters. The filters are EU5 (Eurovent 4/5),
filtration class G4 (CEN standards).
EU6, EU7 and EU8 filters
Optional 290mm high efficiency filters, class EU6, EU7 and
EU8 (Eurovent 4/5), are available on request. The filters are
made of fiberglass filter media. The filter media is
constructed in ”V” sections with a rigid external frame to
withstand high pressure drops and flow variations.
Ifthese filters areordered, a 600mmfilter plenum isrequired
to house them. The plenum is of the same colour as the unit
and installed on the top of the unit. (Refer to Options section
of the Technical Data Tables for details).
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Figure 12 - EU6, EU7, EU8 Filters

Optional features - all models (continued)
Filter clog switch
An adjustable differential pressure switch can be fitted to
initiate a change filter alarm when a pre-selected pressure
drop across the filter bank is exceeded.
Water detection sensors
A water detection sensor, containing an isolated switch that
closes when water (or other conductive liquid) is detected by
the sensor probes may be ordered as an option. The sensor is
hermetically sealed, robust and should be fitted in the
location where water problems might occur.
Smoke alarm
A smoke detector/alarm is available as an option. The smoke
detector will activate the alarm and stop the unit if smoke is
detected in the return air. The sensor is an optic smoke
detector (Tyndall effect) which is insensitive to light or air
movement.
Firestat
A firestat/alarm is available as an option. The firestat
deactivates the unit when the return air temperature is too
high. The firestat can be mounted in the unit or remotely,
consult Applications Engineers for details. The detector is
complete with an NTC thermistor.
Environmental Alarm Package
The Electronic Environmental Alarm Package (EEAP) is a
remote temperature and relative humidity sensor (additional
to the internal sensor) connected to the unit controller.
The sensor can be installed up to 20m from the unit and
generatesan alarmif thetemperature or therelative humidity
exceeds one of the 4 user-set limits:
•HighTemperature Limit
(Adjustable from 10°C to 50°C)
•Low Temperature Limit
(Adjustable from 0°C to 30 °C)
•High Humidity Limit
(Adjustable from 30% to 99%)
•Low Humidity Limit
(Adjustable from 10% to 70%).
Fresh air kit
The fresh air intake kit is recommended for use where the
conditioned space is continuously occupied. The kit consists
of a cylindrical EU3 filter mounted in the unit which
connects to a 100mm diameter duct (the flexible duct can
also be supplied if the length is specified).
The fresh air is then mixed with the discharge air from the
unit through a slot on the intake side of the fan.
Floorstand
Floorstands are available in a range of heights, 300mm,
500mm and 800mm. Each height of floorstand is fitted with
adjustablelegs(±25mm).Thefloorstandspermitinstallation
andconnectionofthesystempriortoinstallationoftheraised
floor.
Turning vane
Afactoryinstalledturningvanemaybespecifiedtodirectthe
air as required within the floorstand.
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Figure 13 - Floorstand

Optional features - all models (continued)
Base module - upflow units only
A 200mm base module can be supplied on request to support
upflow Challenger Plus units. The module is used when
customer connections must be made through the base of the
unit, but no false floor is available.
Alternatively the base module can be used for bottom air
return where there is no raised floor.
Sound attenuation package
In applications where sound emission from the unit is of
critical importance, a special sound attenuating cartridge,
attached to the top of the unit, is available to reduce sound
levels to an absolute minimum.
The cartridges, made of a self-extinguishing material with a
high attenuation capacity are guaranteed against
disintegration and release of particles due to friction within
the duct.
It is possible to install one or two rows of cartridges in the
plenum depending on the sound attenuation required. A
single row requires a 600 mm high plenum, two rows require
a 1200 mm high plenum.
A single cartridge in a 600mm high plenum provides a noise
reduction of -8.5 dB(A) at 2 m in front of the unit and 1.5 m
from the ground. A single cartridge in a 1200mm high
plenum provides a noise reduction of -13 dB(A) at 1 m in
front of the unit and at an angle of 45oto the unit top.
Adoublecartridgeina1200mmplenumwillprovidesanoise
reduction of -9.5 dB(A) at 2 m in front of the unit and 1.5 m
from the ground. It will provide a noise reduction of -14
dB(A) at 1 m in front of the unit and at an angle of 45o to the
unit top.
Refer to the Options section of the Technical Data Tables for
further details.
Special packaging
Where the unit is to be transported by sea or in other cases
where heavy duty packaging is required, special crating is
available.
This can consist of either a wooden crate over the standard
carboard/bubble wrap packaging or the entire unit can be
encased in a wooden box.
Specialpackingforseatransport,consistingofawoodenbox
or crate in addition to normal cardboard, can be supplied on
request.
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Figure 14 - Base Module
Figure 15 - Sound Attenuation Cartridge
Figure 16 - Special Packaging

Optional features - all models (continued)
Plenum
Anintake/supplyplenumisavailableforconnectionbetween
theunitandafalseceiling.Theplenum ismanufacturedfrom
the same material and in the same colour as the unit.
The plenum consists of sandwich panels lined with class 0
(ISO 1182.2), 30 kg/m3 density, non-flammable insulation.
Available heights range from 600 mm to 1200 mm.
Plenum with fixed grille (upflow)
A supply air plenum with fixed horizontal air flow can be
installed on top of the unit. The 900 mm high plenum is
manufactured from the same material and in the same colour
as the unit.
The plenum consists of sandwich panels lined with class 0
(ISO 1182.2), 30 kg/m3 density, non-flammable insulation.
Plenum with adjustable louvered grille
(upflow)
A supply air plenum with adjustable (up and down) air flow
canbeinstalledontopoftheunit.The900mmhighplenumis
manufactured from the same material and in the same colour
as the unit.
The plenum consists of sandwich panels lined with class 0
(ISO 1182.2), 30 kg/m3 density, non-flammable insulation.
Caution is advised against extreme deflection of the louvers
as this can obstruct the air flow and reduce the unit’s cooling
capacity.
Condensate pump
A condensate drain pump can be supplied if required. The
pump is complete with a flow cutout switch allowing the
pump to stop and reset automatically. Depending on the unit
type,it canbe suppliedfitted orloose forfield fitting,consult
Liebert Applications Engineers for details. The following
table lists pump capacity vs. available head.
Flow (l/s)0.0830.1670.2500.333
Available Head (kPa)20 19 18 14
Air intake from the bottom (upflow
models)
Upflow models are normally front return. If required, they
can be supplied as bottom return. Bottom return models are
fittedwith a blankfront panel (thisreduces the soundlevel of
the unit).
Dampers
Challenger Plus units can be provided with motorised
shut-off dampers for downflow models and gravity-fed
dampers for upflow models.
Alternative refrigerant R407C
Anoptional “green” refrigerant,R407C can besupplied with
all compressorised models.
The compressor is filled with a special ester oil required for
R407C. Air cooled units are filled ex-factory with a holding
charge of dry nitrogen. Water, Dual Source Water and
Freecooling units are charged with R407C.
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Figure 17 - Plenum with grille