McQuay PFSB 103.1, PFSB 124.1, PFSB 147.1, PFSB 229.2, PFSB 208.2 Product Manual
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Product Manual
803 B – 04/11 D
Data: November 2004
Supersedes: 803 B-02/09 C
McQuay is participating in the Eurovent Certification Programme.
Product are as listed in the Eurovent Directory of Certified Products
and on the web site www.eurovent-certification.com
New water cooled screw chillers McQuay PFS “B”
McQuay International introduces their newest water cooled screw chillers equipped with new single screw
compressors.
McQuay water cooled PFS chillers equipped with 1 or 2 McQuay screw co mpressors are a new range of the unit
using the StarGate
the consultants and the end user. McQuay PFS units are designed to minimise energy cos ts while maximising the
refrigeration capacities. Once again McQuay has developed a line of chillers unsurpassed in performance and
quality that will meet the most stringent requirements of comfort cooling, ice storage and process applications.
McQuay’s chiller design experience, combined with outstanding features makes the PFS c hiller unmatched in the
industry.
TM
single screw compressors. They are manufactured by McQuay to satisfy the requirements of
Customer benefits
Design for every kind of requirement
Compared with competitors, PFS water cooled chiller offers surprising performance. PFS dual compressor unit
(with a single refrigerant circuit) takes full advantage of the total heat transfer surface over the use of two separate
refrigerant circuits when only one compressor is required to satisfy the thermal load.
McQuay has answered the challenge to create a reliable, energy efficient, environmentally safe with the
introduction of the new PFS screw compressor water-cooled chiller.
Lower noise – higher flexibility
The McQuay original compressor design with a single screw and twin rotors allows a constant gas flow. This
compression process completely eliminates gas pulsations. The oil injection also results in significant mechanical
noise reduction.
The twin gas compressor discharge chambers are designed to act as attenuators, based on the harmonic wave
principle with destructive interference, thus always resulting equal to zero. The extremely low noise compressor
performance affords the use of PFS chiller for all applications.
The reduced number of vibrations produced from the PFS chillers offers a surprisingly quiet operation eliminating
the noise transmission through the structure and the chilled water piping system.
Infinitely variable capacity control
Cooling capacity c ontrol is infinitely variable by means of a capacity slide controlled by microprocessor system.
Each unit has infinitely variable capacity control down to 12.5% (two compressors units), to 25% (one compressor
units). This modulation allows the compressor capacity to exactly match the building cooling load. The result is a
decrease in chiller energy costs, particularly at the part-load c onditions at which the chiller operates most of the
time. In order to optimize control sequence, each compressor load (and unload) from 95 to 100 % of its capacity
by one step.
Unmatched serviceability
Field serviceability has not been sacrificed. Inspection covers allows visual inspection of the main screw and
gaterotors. Suction valves allow easy isolation and field servicing of this unit.
Outstanding reliability features
Full factory testing of all the units ensures a trouble free start-up. Extensive test makes certain that each safety
and operating control is properly adjusted, and operates correctly.
803 B – 04/11 D – pag. 2/24
803 B – 04/07 D – pag. 2/24
General characteristics
Ecological HCF 134a refrigerant
McQuay has designed and optimized StargateTMcompressors to operate with HFC 134a, ecological refrigerant
with zero ODP (Ozone Depletion Potential) and very low GWP (Global Warming Potential) that means low value of
the “direct effect” in the formula of TEWI (Total Equivalent
Warming Impact).
Screw compressors
The newes t StargateTMsingle-screw compressor has a well
balanced compression mechanism which cancels the screw
rotor load in both the radial and axial directions. Inherent to
the basic single-screw compressor design is the virtually
load-free operation, that gives main bearing des ign life of 3-4
times greater than twin-screws, and eliminates expensive
and complicated thrust balancing schemes. The two exactly
opposed gaterotors create two exactly opposed compression
cycles. Compression is made at the lower and upper parts of
the screw rotor at the same time, thus cancelling the radial
loads. Also, both ends of the screw rotor are subjected to
suction pres sure only, which cancels the axial loads and
eliminates the huge thrust loads inherent in twin-screw
compressors.
Oil injection is used for these compressors in order to get
high COP at high condensing pressure. PFS units are
provided with an high efficiency oil separator to maximise oil
extraction.
Compressors have a infinitely va riable capacity control down
to 25% of its total capacity. This control is made by means of
capacity slides controlled by microprocessors.
Standard start is star-delta type; Soft start type is available
(as option) in order to have lower inrush current.
Evaporator
Flooded shell-and-tube evaporator operating with refrigerant in shell and water in tubes. Replaceable water tubes
are fabricated from integral finned copper and mechanically bonded to steel tube sheets. The evaporator is PED
designed, constructed, inspected and stamped. Water side working pressure is designed for 10,5 bar. Vessels
include 1” FPT spring loaded pressure relief valves. Shell and non-connection water heads are insulated with 3/4”
thick closed cell insulation. Standard configuration on water connections side is 2 passes.
Condenser
Shell-and-tube type operating with refrigerant in shell and water in tubes. Replaceable water tubes are fabricated
from integral finned copper and mechanically bonded to steel tube sheets. Condenser is designed to conform
PED. Water side working pressure is designed for 10.5 bar. Standard configuration on water connections side is 2
passes.
Operative efficiency
The majority of comfort cooling systems operate at 60% or less of building design kW for most of the year. A great
number of those operating hours occur between 50% and 60% des ign cooling capacity. For that reason, PFS
chiller was designed to obtain excellent part load performance. This is achieved by a combination of individual
component features that include compressor design, operating control, double heat transfer surface with only one
compressor running (dual compressors unit), refrigerant flow control.
803 B – 04/11 D – pag. 3/24
Servo Controlled modulating liquid level regulators
PFS are equipped with a modulating servo-controlled main expansion valve type controlled by a pilot float valve
type to perfectly modulate refrigerant flow to the evaporator, proportionally to the required capacity. This ensures a
stable regulation and economic operation, because pressure and temperature variations are strongly reduced.
Electrical panel
Power and control are located into two sections of the main panel that is manufactured to insure protection for all
weather conditions.
The power panel is fitted with a interlocked door main isolator to prevent access while power supply is on.
Electrical panel is IP43.
Power section includes - The power section includes contactors, all compressors fuses, and control circuit
transformer. Additional space is provided for an easy installation of the various optional accessories provided to
enhance the PFS units capabilities.
Certifications
All the PFS units are CE marked (89/392). McQuay Italia obtained ISO 9001:2000.
Water content in cooling circuits
The cooled water distribution circuits should have a minimum water content to avoid excessive compressors start
and stop.
In fact, each time the compressor starts up, an excessive quantity of oil goes from the compressor sump and
simultaneously there is a rise in the temperature of the compressor motor’s stator due to the inrush current during
the start-up. To prevent damage to the compressors, McQuay has envisaged the application of a device to limit
frequent stops and restarts.
During the span of one hour there will be no more than 6 starts of the compressor. The plant side should therefore
ensure that the overall water content allows a more constant functioning of the unit and consequently greater
environmental comfort. The minimum installation water content envisaged should be calculated with a certain
approximation using this simplified formula:
(1) Q = 35,83 X
(kW)P
°∆
where:
Q = Minimum content of the plant expressed in litres
P = Cooling capacity of the plant expressed i n kW
∆T = Entering/leaving water temperature difference of the evaporator expressed in °C
N = Number of compressors.
For a more accurate determination of the quantity of water, it is advisable to contact the designer of the plant.
1
X
)C(T
N
803 B – 04/11 D – pag. 4/24
Microtech II Plu s controller
Microtech II Plus device is installed as standard on all the units; it can be used to alter unit set points and control
commands. A display illustrates the machine's operating status and programable parameters (setpoints) e.g.
temperatures and pressures of fluids (water, refrigerant). Device controls maximise the McQuay chillers energy
efficiency and reliability characteristics. It uses sophisticated software with predictive logic to select the most
energy ef ficient combination of compressor. The compressors are automatically rotated to ensure equal operating
hours. Microprocesso r device protects critical components in response to e xternal signals from its system sensors
measuring: motor temperatur es, refrigerant gas and oil pressures, electrical supply and evaporator.
Control section - main features:
• Management of the compressor capacity slide according to the distributed multiprocessor logic system
• Chillers enabled to work in partial failure condition thanks to the distributed multiprocessor logic system
• Full routine operation at condition of:
High thermal load
High evaporator entering water temperature (start-up)
• Display of evaporator entering/leaving water temperature
• Display of condensing-evaporating temperature and pressure, superheat temperature for each circuit
• Leaving water cooled temperature regulation (also available entering water regulation). Temperature
tolerance=0,2°C
• Compressors and evaporator/condenser pumps hours counter
• Display of Status Safety Devices
• Start up numbers and compressors working hours equalization
• Excellent management of compressors load
• Automatic re-start in case of power supply interruption
• External signal demand limit 0÷100%
• Soft load: starting load limitation (25÷100%) time based
• External air reset
• Current limitor
• High evaporator temperature start
Safety for each refrigerant circuit
High pressure (pressure switch)
Low pressure (pressure switch)
Compressor thermal
High Discharge Temperature on the compressor
Phase Monitor
Star / Delta Transition Failed
Low Delta Pressure between Suction and Discharge
System security
A serious alarm input (stops the unit)
A flow controller input (stops the unit)
A pump thermal input (stops the unit)
Remote on/off i nput without alarm signaling
Regulation type
Stabilized PID Proportional - Integral – Derivative regulation on the evaporator input probe for a perfect water
regulation (max ∆T=±0,2°C)
803 B – 04/11 D – pag. 5/24
Microtech II Plus terminal
The Microtech II Plus terminal has following features:
• 4-lines by 20-character liquid crystal display
• Removable and remote key-pad
• Key-pad consisting of 15 keys “ clear language display ”
• Memory to protect the data
• General faults alarm led
• 4-level password acc ess to modify the setting
• Service report dislaying all working hours and general conditions
MicroPlantTM:
Solution for: tele-maintenance and supervisory systems
Microtech II Plus can be monitored locally or via modem by MicroPlant supervision program, that runs on PC
systems under Windows ’95 – ’98.
MicroPlant is the best solution:
• To centralise all the information in just one local and/or remote PC
• To check all the parameters for each unit connected
• To be informed immediately and automatically of any alarm situation via
modem - printouts
• Automatic printouts of alarms, parameters and graphs
• To control s everal plants located in different geographical areas from a
central station
• To manage the Service centers
MicroPlant allows:
• Visualization and modification of all the parameters for each controller
• Protection of the main parameters against incidental modifications
(different levels of passwords)
• Memorization of the detected values and visualization of their graphics
• Display, print-out and chronological memorization of the detected alarms
• Connection between local and remote computer via telephone line
(Modem)
Microtech II Plus remote control
Compatibility with supervisory systems is becoming
increasingly important in HVAC. Microtech II Plus allows
easy interfacing with BMS (Building Management Systems),
the external world that can be:
Landis & Staefa, Siemens, Johnson, Honeywell, Satc hwell,
Trend.
McQuay Chiller System Controller (CSC) is available as
option.
803 B – 04/11 D – pag. 6/24
Standard Accessories (furnished on basic unit)
Modulating condenser water flow valve – Factory mounted on condenser outlet water connection, in order to
allow fast and safe unit starting. It is not supplied for condensers with water side pressures higher than 10 bar.
Discharge line check valve – Ensures compressors maintainence operations without any refrigerant loss.
Star Delta Compressors starter – For low inrush current and reduced starting torque.
Phase monitor – The phase monitor controls the voltage values on the supply line s topping the unit when the
calibration threshold is reached (± 10%). This safety device is automatically reset.
Evaporator connection w ater side Victaulic – Hydraulic joint with gasket for an easy and quick water
connection.
Insulation around the evaporator – Ins ulation 20 mm thickness to protect the evaporator against freezing.
Hour run meter – Digital compressors hour run meter.
General fault contactor – Contactor for the alarm warning.
Options (on request)
Brine double set point version (CB) - Dual leaving glycol mixture temperature setpoints. The lower setpoint can
go down to -8°C.
Compressor thermal overload relays - Safety devices against compressor motor overloading in addition to the
normal protection envisaged by the electrical windings.
Ammeter and voltmeter - Digital meters of unit drawn amperes and voltage values, installed on the electrical
control panel.
Condenser power factor correction - Installed on the electrical control panel to ensure it conforms to the plant
rules. (McQuay advices maximum 0,9).
Suction line shut off valve – Suction shut-off valve installed on the suction port of the compressor to facilitate
maintenance operation.
Flanged connections – Evaporator and condenser flanged connections (150 psig) are available instead of the
standard victaulic connections.
Marine water boxes – Evaporator and condenser can be furnished with marine water boxes with victaulic or
flanged connections (on request). To save time and work marine water boxes cover can be easily removed to
clean internal tubes without the disconnec tion of water pipes.
Double water pressure differential switch – Factory mounted differential switch is available as option to detect
evaporator and condenser loss of flow .
Flow switch - Supplied separately to be wired and installed on the evaporator water piping (by the customer).
Cu-Ni 90-10 condenser – To work with sea water the heat exchangers are fitted with Cu-Ni tubes and special
protection inside the end covers.
Rubber type antivibration mounts ( Pads ) - Supplied separately, must be positioned under the base of the unit.
Sound proof cabinet - Made of sheet metal and internally insulated, the cabinet is "integral kind" ( around the
whole chiller, not only around the compressors ) to reach the best performance in noise reduction.
Note: to realize the baseframe consider that the dimensions of the sound proof cabinet are 300 mm longer, 300 mm wider and
200 mm higher than the standard unit. The cabinet is supplied in a separated non assembled kit.
Witness tests - The units are normally tested at the test bench prior to the shipment. On request, a second test
can be carried out, at customer’s presence, in accordance with the procedures indicated on the test form. (Not
available for units with Glycol mixtures).
Soft start – Electronic starting device to reduce inrush current.
803 B – 04/11 D – pag. 7/24
Installation notes
Warning
Installation and maintenance are to be performed only by qualified personnel who are familiar with local codes and
regulations, and who are experienced with this type of equipment. Must be avoided the unit installation in places
that could be considered dangerous for all the maintenance operations.
Handling
The chiller is mounted on heavy wooden skids to protect the unit from accidental damage and to permit easy
handling and moving. It is recommended that all moving and handling be performed with the skids under the unit
when possible and that the skids not be removed until the unit is in the final location.
If the unit must be hoisted, it is nec essary to lift the unit by attaching cables or chains at the lifting holes in the
evaporator tube sheets. Spreader bars must be used to protect the control cabinet and the other areas of the
chiller.
Location
A levelled and sufficiently strong floor is required.
Rubber-in-shear isolators can be furnished and field placed under each corner of the package. A rubber anti–skid
pad should be used under isolators if hold-down bolts are not used.
Vibration isolator in all water piping connected to the chiller are recommended to avoid straining the piping and
transmitting vibration and noise.
Evaporator and Condenser water flow and Delta T
Standard configuration on water side connections is 2 passes for both evaporator and condenser. Use pressure
drop curves to check if it’s the best solution.
In order to optimize performances with higher delta T ( lower water flow ), 3 passes evaporator and 3 or 4 passes
condenser configurations are available on request.
Operating Range
60
50
40
30
20
Condenser leaving temperature - °C
10
0
-10 -5 0 5 10 15 20
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Evaporator leaving temperature - °C
Note:
the use of glycol is necessary
803 B – 04/11 D – pag. 8/24
for
evaporator leaving water temperature below +3°C.
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