reversible chillers and heat pumps - lew series high ... · page 4 of 28 rg66009172‐rev.00 1...

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Reversible Chillers and Heat Pumps - LEW SERIES

HIGH CAPACITY RANGE

480 - 630 kW

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For further information or communication, please contact the company at:[email protected] To find out the weight of each unit, please refer to the table in the paragraph “Rated specifications”

Declaration of conformity

The declaration of conformity is attached to each machine

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Contents

HIGH CAPACITY RANGE ......................................................................................................................... 1

CONTENTS ...................................................................................................................................................... 3

1 GENERAL DESCRIPTION .................................................................................................................. 4

1.1 THE LEW - BIG RANGE PRODUCT ...................................................................................................... 4 1.1.1 PRODUCT CONFIGURATIONS .................................................................................................................. 4 1.1.2 CONFIGURATION AND ACCESSORIES .................................................................................................... 5 1.1.3 FIELD OF APPLICATION ........................................................................................................................... 6 1.1.4 PRODUCT INNOVATION ........................................................................................................................... 9 1.2 STRUCTURE ............................................................................................................................................... 9 1.2.1 COMPRESSORS ...................................................................................................................................... 10 1.2.2 HEAT EXCHANGERS ............................................................................................................................... 10 1.2.3 DE-SUPERHEATER FOR PARTIAL HEAT RECOVERY (OPTIONAL) ........................................................ 10 1.2.4 UTILITY AND DISSIPATION SIDE CYCLE INVERSION VALVES (SUPPLIED OPTIONALS) .................. 11 1.2.5 ELECTRONICALLY CONTROLLED ELECTRIC EXPANSION VALVE ......................................................... 12 1.2.6 OTHER CHILLING COMPONENTS .......................................................................................................... 12 1.3 � ELECTRICAL CONTROL BOARD ...................................................................................................... 16 1.3.1 CONTROL MICROPROCESSOR ............................................................................................................... 16

2 TECHNICAL DATA ............................................................................................................................... 17

2.1 OVERALL DRAWINGS OF LEW BIG RANGE UNIT .......................................................................... 20

3 INSTALLATION .................................................................................................................................... 21

3.1 INSTALLATION CLEARANCE REQUIREMENTS .................................................................................. 21 3.2 VOLUME OF WATER IN THE SYSTEM ................................................................................................. 21

4 OPERATING LIMITS .......................................................................................................................... 23

4.1 WORKING LIMITS ................................................................................................................................. 24 4.2 WATER FLOW TO EVAPORATOR ......................................................................................................... 24

5 CALIBRATION OF CONTROL DEVICES ................................................................................... 25

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1 General description

1.1 The LEW - Big range product LEW reversible water chillers and heat pumps are air or process fluid conditioning units, designed for both domestic and industrial use and in operation 24 hours a day. They cover a thermal output range from 450 to 600 kW, guaranteeing high‐level thermodynamic performance and a wide range of configuration possibilities, both in accessories and cooling circuit. LEW machines have been built in a fully faired framework making the unit extremely silent, which enables installation in open environments without needing to be closed off. The use of R410A refrigerant and of high‐quality components in the chiller, hydraulic and electrical parts makes the LEW units state‐of‐the‐art chillers in terms of efficiency, reliability and emitted sound output.

1.1.1 Product configurations

The series of LEW models consists in a wide range of products, meeting all system needs: LEW C water chillers‐cold water only LEW D water chillers‐cold water only (interlocked by Dry‐Cooler or Evaporative turret) LEW H water heat pumps‐chiller side reversible water LEW W water ‐ water only heating heat pumps All versions listed are available in sizes expressed in terms of rated cooling capacity [kW], obtained in conditions with chilled water produced at 7°C and combined with the evaporative turret with dissipation water circuit at 29° inlet and 35° outlet. All sizes of the LEW series can be implemented with the standard "S" set‐up or the "L" soundproof set‐up, covering the compressor and outer panelling with soundproof material. The LEW units are identified with the following symbol:

LEW 636 CS 1 ‐ Identification symbol of Model (e.g.: “LEW” unit) 2 ‐ Unit sizes expressed in rated chilling output x10 [kW] (e.g.: 630 kW) 3 ‐ Efficiency Pack: cooling circuit and compressor layout (e.g.: 6 compressors in 2 chiller circuits) 4 ‐ Machine version (e.g.: “C”, Chiller) 5 ‐ Machine execution (e.g.: “S” soundproofing not available)

1 2 3 4 5

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1.1.2 Configuration and accessories

List of standard features R410A refrigerant

Scroll compressors

Galvanised and painted sheet-metal structure

Flow switch included

Brazed plate heat exchangers

Second set point on utility side that can be activated from an external input

List of options Version CMP-1

Chiller condensed with well or mains water C

Chiller condensed with water from a dry-cooler or evaporative tower D

Reversible heat pump H

Non-reversible heat pump (hot only) W

Execution CMP0

standard S

low-noise L

1 - Electric power supply CMP1

400/3/50 + N 0

400/3/50 + Motor circuit breakers 2

2 - control microprocessor and expansion device CMP2

base + electronic expansion valve 0

base + mechanical expansion valve A

programmable (LCD display 8x22) + electronic expansion valve B

programmable (LCD display 8x22) + mechanical expansion valve C

3 - Partial heat recovery (mandatory condensation control) CMP3

absent 0

de-superheater (40% Pf recovered under normal circumstances) D Not available if Field 4 = 0

4 - Flow rate modulation on source side CMP4

absent 0

condens. control with 0-10V modulated output signal P Not available if Field 2 = 0,A

5 - Flow rate modulation on utility circuit CMP5

absent 0

6 - Remote communication CMP6

absent 0

RS485 serial board (Carel or Modbus protocol) 1

Serial board Lonworks 2 Not available if Field 2 = 0,A

GSM modem kit 3 Not available if Field 2 = 0,A

Ethernet board (SNMP or BACNET protocol) + clock board 4 Not available if Field 2 = 0,A

Ethernet board + clock board + supervision software 5 Not available if Field 2 = 0,A

7 - Vibration isolation CMP7

absent 0

Rubber anti-vibration mounts at base of outdoor unit G

Spring anti-vibration mounts at unit base M

8 - Package CMP8

standard 0

wooden cage 1

wooden cage 2

9 - Remote control CMP9

absent 0

Simplified remote control panel 1

Remote display for standard microprocessor 2 Not available if Field 2 = B,C

Remote display for programmable microprocessor 3 Not available if Field 2 = 0,A

10 - External insulated hydraulic module separated from the main unit CMP10

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No hydraulic module 0

List of accessories Shunt condensers A

Soft-starter kit B

Service kit (probe kit for quick diagnostics) C Not available if Field 2 = 0,A

Clock board D Not available if Field 2 = 0,A

ON-OFF status of compressors E

Remote contact for (step-based= power limitation F Not available if Field 2 = 0,A

Configurable digital alarms board G Not available if Field 2 = 0,A

Pressure gauges H Not available if Field 2 = 0,A

G - Four Vic-Taulic joints for quick water IN-OUT connection I

Filter cut-off kit (solenoid and cock on liquid line) L

Outdoor temperature sensor for set-point compensation M Not available if Field 2 = 0,A

Dissipation side water temp. probe for Version = "H" or "W" N

1.1.3 Field of application

LEW units are designed for cooling‐heating water and solutions containing up to 30% glycol (percentage by weight) in civil, industrial and technological air‐conditioning systems. The units cannot operate outdoors, as the metalwork provides an IP43 insulation. Please contact the technical office for these applications.

LEW series units must be used within the operating limits shown in this document or the warranty required by the sales contract will be voided.

LEW multifunction machines have 4 water connections associated with two different water circuits for 2‐pipe systems: Circuit 1, production of cold or hot water for utility; Circuit 2, production of hot or cold water for dissipation in opposition to the utility; Accordingly, the multifunction units have 2 heat exchangers: Plate heat exchanger 1 with both evaporation and condensation function, intended for the utility circuit; Plate heat exchanger 2 with both evaporation and condensation function, intended for the dissipation circuit; LEW chiller unit: view of the thermodynamic circuit. For gas and water connection directions, refer to the dimensional drawing attached to the documentation.

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LEW C machines are designed for cold‐only production: in the utility circuit only the production of chilled water is envisaged. The LEW H machines are reversible heat pumps: in the utility circuit hot water and chilled water can be produced alternatively. The following points briefly illustrate the operating functions of the LEW C, D, H, W units: Chilling LEW C, D, H units in “Chiller” mode cool the water to cool down the environment on the utility side, thereby dissipating condensation heat with the water cooled by the dissipation heat exchanger.

Heating LEW H, W units in “Heat Pump” mode heat the water in the condenser to heat the utility side, thereby dissipating the evaporation cooling capacity by means of the water which is heated in the dissipation heat exchanger. In other words, a certain amount of heat is drawn from a thermal source and is then transferred to the utility after it has reached a sufficient thermal level that is suitable for its needs.

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Air‐conditioning applications often need to be able to dispose of heat to heat up domestic hot water or for post‐heating control in air treatment facilities where an autonomous Temperature and humidity control will be implemented. The heat required can be drawn from the condensing section of the thermodynamic unit, which is at a higher temperature. If only part of the heat is drawn, a de‐superheater sends gas‐sensitive heat to the delivery pipe towards the third thermal source at a higher temperature.

Upon specific demand, all cold‐only units of the LEW series can be equipped with a de‐superheater for partial heat recovery. The available thermal output that can be used for domestic hot water, for example, depends on the unit's operating conditions.

Layout of partial heat recovery circuit

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1.1.4 Product innovation

LEW units provide excellent thermodynamic performance and maximum flexibility of use thanks to constant product research. The joint application of scroll compressors, advanced control systems and R410A refrigerant gas bring about compact circuit and high‐level COP. The possibility of keeping the evaporator on the inside allows you not to add glycol to the water in the system, with clear advantages in terms of thermodynamic performance, preservation from corrosion and respect for the environment. It also makes it possible for all the components requiring maintenance to be installed in an easily accessible space. Chiller units can be applied even when no dissipation source other than air is available: a water Dry‐Cooler provides thermal exchange with the atmosphere while maintaining a compact‐sized circuit. The main innovations which this product presents are summarised in the following list: Option of using water without glycol in the utility circuit Heat pump mode with chiller side cycle inversion Option of even heat pump versions using condensation control Electronically controlled electric expansion valve High COP (Coefficient of performance) of thermodynamic cycle Reduced refrigerant load Option of applying chiller mode even when air is used as dissipation source It occupies less space on the floor‐plan (specific powers up to 153 kW/m2) Innovative aesthetic features and full safety since units are completely closed No noise on the outside, less noise on the inside due to dual‐soundproofing in low‐noise versions.

1.2 Structure All LEW series units have the load bearing base and panelling in galvanised sheet metal painted with polyester powders and polymerised in the oven at 180°C. The unit is attractively designed and when closed all the components are inaccessible. This, along with the extensive use of soundproofing material inside the compartment and around the compressors (available for the low‐noise version), reduces sound to exceptionally low levels. The hydraulic/chiller connections are envisioned on the right side, when looking at the electrical control board, to reduce the technical space required for installation. All the panels are removable (except for the one on the right, upon which all the hydraulic connections are fitted) making the unit fully accessible even though routine maintenance only needs accessing from the front.

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1.2.1 Compressors

Only top international brand Scroll compressors are used on LEW units. The Scroll compressor is the best solution today in terms of reliability and efficiency in the range of power outputs up to 300 kW for each circuit and the best solution in terms of emitted sound output. Process optimisation, along with a carefully selected intrinsic volumetric compression ratio (RVI), clearly improves the isentropic compression performance and reduces energy losses. The use of a scroll compressor allows low viscosity oils to be used. This, in comparison to higher viscosity oils, reduces thermal resistance at the evaporator. It also increases the evaporation temperature by more than 1.5°C (EER increases by more than 5.5%) compared to other solutions. Compressor motors are protected against overheating, overloads and high delivery gas temperatures. They are mounted on rubber anti‐vibration mounts, complete with oil charge and inserted in a soundproof compartment with sound‐absorbing material. Also complete with automatic oil heater to prevent the oil from being diluted by the refrigerant when the compressor stops.

NOTE: Scroll compressors, like all air‐tight compressors, are classified as pressurised containers. The low pressure section, referred to by the PS on the data plate, complies with PED CE 97/23.

1.2.2 Heat exchangers

Only brazed plate heat exchangers are used, made of austenitic stainless steel AISI 316 with AISI 316L connections, featured by a reduced carbon content to simplify brazing operations. The solution of the brazed plate heat exchanger represents the state‐of‐the‐art in terms of thermal exchange efficiency and allows a strong reduction of refrigerant load compared to standard solutions. The high level of turbulence generated by internal plate corrugation, along with plate smoothness, makes it difficult for dirt to accumulate or for limescale to build up on the condenser circuit. These heat exchangers also make it possible to use R410A fluid which, thanks to the high‐level thermal conductivity of its liquid phase and to its azeotropic behaviour, enhances thermal exchange during evaporation. The performances are improved over other methane‐derivative fluids of the HFC group.

NOTE: due to thermal insulation, the data plate in compliance with PED CE 97/23 is not legible, but the serial number of the heat exchanger and the declaration of conformity are detected during production and are an integral part of the Galletti archive.

1.2.3 De-superheater for partial heat recovery (optional)

The option of partial heat recovery is implemented with a braze‐welded plate heat exchanger placed in series on the finned pack condenser and its size limits pressure drops on the refrigerant side to a minimum. All machines configured with heat recovery use as per standard modulating condensation control. To prevent a lack of balance in the cooling circuit, if the water temperature is too low when the recovery starts, the hydraulic recovery circuit is implemented as indicated in the following figure: a low water temperature at recovery would cause a drop in

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the condensation temperature and therefore an insufficient pressure jump on the expansion valve with the ensuing risk of the safety devices being triggered.

The bulb of the 3‐way mixer valve is placed at the de‐superheater exchanger inlet, which by mixing the hot water produced with colder water from the tank allows you to limit the time needed for the system to reach full operating capacity to a few moments. A buffer tank must be placed between the unit and the utility since the demand for hot water and its availability are not simultaneous, because it needs the compressors to be running. It should be pointed out that the heat recovery output is linked to the dispensed cooling output and that, therefore, in partial load situations it is also reduced just the same; this aspect must be taken into consideration for the dimensions of the buffer tank. The partial heat recovery option is supplied only with the de‐superheater exchanger. The other components of the circuit laid out in the previous figure are not included in the supply.

1.2.4 Utility and dissipation side cycle inversion valves (supplied optionals)

When LEW H reversible chillers switch from chiller to heat pump, and vice versa, they may perform two cycle inversions: one on the coolant circuit and one on the water circuit. The inversion valve of the water‐side cycle switches from position A to position B and vice versa by means of an electrical driver without changing the direction of travel for the outside utilities. This allows you to invert the direction of the flow in the heat exchangers, keeping them against the flow in relation to the refrigerant fluid in every operating mode. The water‐side cycle inversion valve is an optional component.

TANK

VALVE RECIRCULATION PUMP H

EAT

EXCHANGER

UTILITIES

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Refrigerant side cycle inversion valve Heat‐transfer fluid side cycle inversion valve

1.2.5 Electronically controlled electric expansion valve

The electronically controlled valve with external equalisation and built‐in MOP function is managed by the software and therefore makes cooling circuit operation very efficient, stabilising and decreasing the power absorbed by the system when a sudden thermal load variation occurs. The shutter in the central part of the valve can always slide vertically with an ample stroke allowing variation of the degree of opening of the orifice of the fluid passage. Using this valve reduces compressor energy consumption when the surrounding conditions bring the pressure difference between the evaporator and the air conditioner below 5 bar, thus improving performance.

1.2.6 Other chilling components

‐ Molecular sieve filter dryer ‐ Sight glass with humidity indicator ‐ One‐way valves (only reversible heat pump) ‐ Liquid receiver marked in compliance with EC Directive 97/23 PED (only reversible heat pumps or units with remote

condenser) ‐ High and low pressure switches Schrader valves for control and/or maintenance

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Diagram of the dual‐circuit cold‐only version (please note: this is a standard layout, refer to the layout enclosed with the unit). To consult the layouts, please refer to the symbols in the following table.

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Diagram of the dual‐circuit reversible heat pump version (please note: this is a standard layout, refer to the layout enclosed with the unit).

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Reference table for numbering used in layouts

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1.3 � Electrical control board The electrical control board is built and wired in accordance with standard EN 60204‐1. The electric panel is accessed from the front of the machine. Before it can be accessed, the unit must be disconnected from the power supply using the main switch, which functions as a door‐lock. All the remote controls are implemented with low voltage signals at 24 V, powered by an isolation transformer positioned inside the control board. All the control boards have an air circulation system with auxiliary fans. The position of the main switch makes wiring operations in the work site easier. This avoids several difficult operations as well as having to twist the power cords. All of the utilities are protected against surges and short circuits and it is possible to configure the circuit breaker set‐up for every load (optional): however thermal protection is already implemented by thermistor chains plunged in the windings of each electric motor and adequately controlled by on‐board electronics. All machines are equipped with a standard phase sequence relay which inhibits compressor operation if the phase sequence is not observed: only one direction of rotation is possible with scroll compressors.

1.3.1 Control microprocessor

LEW series units have two different microprocessor control levels: ‐ Basic – Carel µChiller ‐ Advanced – Carel series pCO The latter, in addition to the functions described below, can customise the software to meet all system requests. These include cascade management of the units with step‐control or cascade logic. The microprocessor on board the unit controls the various operating parameters with an electric panel keypad;

‐ Compressor connection/disconnection to maintain the set‐point of the chiller inlet water T; ‐ Alarm management: High / low pressure; Antifreeze / Flow switch; Pump alarm ‐ Alarm signals ‐ Display of operation parameters ‐ Evaporator anti‐freeze protection ‐ Control of maximum number of compressor starts ‐ RS232, RS485 serial output control (optional) ‐ Incorrect sequence phases (not viewed on display, but keeps compressor from starting)

As for remote communication, the controls can be connected to advanced BMS systems. The HSD (Galletti Software Department) structure is capable of assisting customers in integration operations. System interconnectivity capabilities are summarised below: ‐ Available serial ports

‐ RS232 ‐ RS485 ‐ Ethernet (“HiWeb” board)

‐ GSM Modem: with prepaid card and relative antenna on board the machine for autonomous two‐way control of alarms and/or set‐point variations

‐ Protocols ‐ Carel [Built‐In] ‐ Modbus® [Built In with Advanced controls] ‐ Modbus® [With external gateway with Basic controls] ‐ LonWorks® [Dedicated serial board to be requested when ordering the machine] ‐ BACnet™ [With external gateway] ‐ TCP‐IP [With external gateway] ‐ TREND® [Dedicated serial board to be requested when ordering the machine]

(ref. Microprocessor control manual for further details)

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2 Technical data

The following chapter provides the technical data for the LEW Big range unit. Performance values are accurately reported and can be interpolated to know specific operating conditions. Table I – Technical data of LEW C chillers in standard operating conditions Name LEW 485 CS LEW 535 CS LEW 576 CS LEW 636 CS

Water. In/Out temp. utility side °C 12 / 7 12 / 7 12 / 7 12 / 7

Ethylene glycol % 0.0 0.0 0.0 0.0

Water In/Out temp. °C 15 / 30 15 / 30 15 / 30 15 / 30


Free path distance (m) 10.0 10.0 10.0 10.0

Directionality factor 2.0 2.0 2.0 2.0

Cooling Capacity kW 506.62 574.68 612.31 681.08

Total Absorbed Power kW 93.88 104.42 114.02 126.89

Total Current Absorbed A 150.55 167.46 182.86 203.49

EER 5.40 5.50 5.37 5.37

Utility side water flow rate l/h 87003.0 98690.0 105153.0 116963.0

Utility Water Pressure Drops kPa 53.0 55.0 53.0 65.0

Source side water flow rate l/h 34283.0 38775.0 41465.0 46126.0

Source Water Pressure Drops kPa 23.0 28.0 32.0 39.0

Maximum current (FLA) [Without Options] A 290.0 256.0 348.0 424.0

Booster current (LRA) [Without Options] A 552.0 551.0 610.0 621.0 Booster current with Soft Starter kit [Without Options] A 406.0 495.0 464.0 565.0

Lw sound output level (base unit) db(A) 84.0 84.0 85.0 85.0

Lp Sound Pressure Level (base unit) @10 m Q=2 db(A) 56.0 56.0 57.0 57.0

Compressors/Circuits 5/2 5/2 6/2 6/2

Refrigerant load kgl 42 46 50 51

Electrical power supply 400 / 3+N / 50 400 / 3+N / 50 400 / 3+N / 50 400 / 3+N / 50

Refrigerant R410A R410A R410A R410A

Dimensions [HxLxD] mm 1490 x 3530 x 1200 1490 x 3530 x 1200 1490 x 3530 x 1200 1490 x 3530 x 1200

Weight without accessories kg 1950.0 1950.0 2100.0 2100.0

Notes: sound emissions of the L silenced units are 4 dB(A) less than standard S units indicated in the table.

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Table II – Technical data of LEW D chillers in standard operating conditions Name LEW 485 DS LEW 535 DS LEW 576 DS LEW 636 DS

Water Temp. In/Out utility side °C 12 / 7 12 / 7 12 / 7 12 / 7









EER 3.52 3.41 3.53 3.37

ESEER according to UNI 14511‐2011 6.61 6.55 6.66 6.54
















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Table III – Technical data of LEW H W heat pumps in standard operating conditions Name LEW 485 HS LEW 535 HS LEW 576 HS LEW 636 HS

Water Temp. In/Out utility side °C 40 / 45 40 / 45 40 / 45 40 / 45









EER 4.87 4.69 4.84 4.66

ESEER according to UNI 14511‐2011 6.61 6.55 6.66 6.54
















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2.1 Overall drawings of LEW Big range unit

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3 Installation

3.1 Installation clearance requirements The hydraulic connections are all foreseen on the right side of the unit, when looking at the front panel. This way the back of the unit can be against the wall. It is essential to ensure the following service spaces: ‐ rear side: at least 1 m to be able to connect the hydraulic piping properly ‐ electric panel side: at least 1 m to guarantee access for inspections and/or for maintenance of components ‐ right side: at least 0.5 m ‐ upper side: at least 1 m in the event of partial heat recovery and gas connections ‐ left side: at least 0.5 m

These distances refer to standard versions of LEW units; the same considerations apply to the optional hydronic modules.

When installing the unit, for safety purposes, make sure that the room temperature does not exceed 50°C (with unit on or off).

3.2 Volume of water in the system The ON/OFF‐type compressors work intermittently, since the cooling power required by the utility is not generally the same as that supplied by the compressor. In systems containing little water, in which the thermal inertia is low, verify that the water content of the delivery section (to users) satisfies the equation below:

NsSh

CcV

V = water content in user section [m3] Sh = specific heat of fluid [J/(kg/°C)] e.g. 2090 [J/(kg/°C)] for water = density of fluid [kg/m3] e.g. 1000 [kg/m3] for water D = minimum time between 2 compressor restarts [s] e.g. 120 [s]

1 m Electric control board

0.5 m 0.5 m

1 m Water connections side

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DT = admissible differential on water T [°C] e.g. 4 [°C] Cc = Cooling Capacity [W] Ns = N° of capacity control steps

A standard feature of LEW units is a device to control the water flow rate (blade-type flow switch supplied). Any tampering with this device will immediately invalidate the warranty. We recommend installing a metal net filter on the water inlet piping.

Warning: Never perform hydraulic connection operations with open flames near or inside the unit.

Inertial Tank Ts °C

Inlet water T

Outlet water T

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4 Operating limits

This paragraph reports a list of operating limits for the LEW chillers relating to the water outlet temperature on the utility side and water inlet temperature at the dissipation exchanger. Operating range of LEW units in cooling mode and heat pump mode:

Water can be produced at temperatures below 5°C (up to ‐10°C) using glycol solutions. This lowers the freezing point as shown in the following table:

Minimum temperature of produced water

5 °C 2°C ‐1 °C ‐5°C ‐10 °C

Percentage in weight of ethylene glycol

0 % 10 % 15% 25 % 30 %

Freezing temperature of mixture

0 °C ‐4 °C ‐ 8 °C ‐14 °C ‐18 °C

If the water produced is below 0°C, a special insulation needs to be applied to the cold pipes to prevent ice from forming. This is why applications with temperatures produced below 0°C must be considered as special applications. The useful head supplied by the pump, at the same volumetric water flow, depends on the glycol percentage as shown in the following table:

Percentage in weight of ethylene glycol

0 % 10 % 15% 25 % 30 %

Reduction percentage of useful flow rate

0 % ‐5 % ‐8 % ‐12 % ‐15 %

Performance loss of the thermodynamic circuit is negligible up to concentrations of 30% glycol, in weight. The machines' performance can be calculated with the selection software.

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4.1 Working limits ‐ Heat transfer fluid: water or mixture of water and max 30% glycol antifreeze ‐ Maximum water side pressure: = 3 bar ‐ Maximum pressure on high pressure side = 45 bar‐r (**) ‐ Maximum ambient T = 45 °C ‐ Minimum ambient T= ‐10 °C ‐ Maximum pressure on low pressure side = 29 bar‐r (*) ‐ Power supply voltage: = +/‐ 10% compared to plate voltage ‐ Maximum storage T = + 50 °C ‐ Minimum storage Temp = ‐ 20 °C (limit set by on‐board electronics) (*) this value can only be reached during storage and determines the saturation pressure of 30 bar‐r of the refrigerant on the low pressure side of the circuit (value which determines its limits). (**) for units with power outputs higher than 140 kW per circuit, a second pressure switch sets the threshold to 40.5 bar.

4.2 Water flow to evaporator The nominal flow rate is based on a temperature differential of 5° C between inlet and outlet water, in relation to the cooling capacity provided at the nominal water (12/7 °C) temperatures. The maximum allowable flow rate is associated with a temperature differential of 3 °C. Higher flow rates cause unacceptable drops in pressure. The minimum allowable flow rate is achieved with a temperature differential of 8 °C. Lower flow rates may result in low evaporation temperatures, which could trigger the safety devices and stop the unit. They may also cause an incorrect distribution or heat transfer in a non‐turbulent or not fully turbulent flow.

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5 Calibration of control devices

All the control devices are set and tested in the factory before the unit is dispatched. However, after the unit has been in service for a reasonable period of time you can perform a check on the operating and safety devices. The calibration values are reported in Tables I and II.

All the servicing operations performed on the control equipment are considered as extraordinary maintenance and must be carried out EXCLUSIVELY BY QUALIFIED PERSONNEL: incorrect calibration values can cause serious damage to the unit and serious injury to people.

Many of the functioning parameters and calibrations of the control systems that affect the integrity of the unit are set by the microprocessor control and are protected by passwords. Table I ‐ Calibration of control devices

Control device Set Point °C Differential °C

Service thermostat ‐ C 12 2

Service thermostat ‐ H 40 2

Table II ‐ Calibration of safety devices

Control device Unit of

measurement Switching it on Differential Resetting

Antifreeze thermostat °C +4 2 Automatic

Maximum pressure switch cat. IV PED

bar 40.5 ‐ Manual

Low pressure safety valve cat. IV PED

bar 29.0 ‐0 / +10% ‐

Minimum pressure switch bar 1.5 1.0 Automatic

Modulating condensation control [optional]

bar 18 10 ‐

Time between two start‐ups of the same compressor

s 480 ‐ ‐

Flow switch alarm delay s 20 ‐ ‐

Low pressure alarm delay s 1 ‐ ‐

Calibration of the maximum pressure switch The high pressure switch stops the compressor when delivery pressure exceeds the calibration value. For power outputs greater than 140 kW per circuit (namely LER162 in single circuit and LEW304 in dual circuit) there are two maximum pressure switches, one set at 40.5 bar and the other at 45 bar. For smaller sizes, there is just one pressure switch set to 45 bar.

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Attention: do not modify the calibration of the maximum pressure switch. Should the latter fail to work, rising pressure causes the high pressure safety valve to open.

The high pressure switch must be reset manually; this is possible only when the pressure drops below the value indicated by the set differential (see Table II). Calibration of the minimum pressure switch The low pressure switch stops the compressor when the intake pressure falls below the set value for more than 120 seconds. It is reset automatically only when the pressure rises above the value indicated by the set differential (see Table II). Calibration of the service thermostat function This function starts and stops the compressors according to the water temperature reading at the chiller unit inlet [water returning from the system]. Refer to the section of the document on the microprocessor control for further details. Calibration of the antifreeze thermostat function The antifreeze probe is located at the evaporator outlet and stops the compressor if the water temperature drops below the preset limit. Together with the flow switch and low pressure switch, this device protects the evaporator from the risk of freezing as a result of faults in the water circuit. Refer to the microprocessor control manual for further details Calibration of the anti‐recycle timer function The timer function prevents excessively frequent compressor starts and stops. It imposes a minimum time lapse of 480 seconds between two successive starts. Refer to the microprocessor control manual for further details.

Never change the delay time set by the manufacturer: incorrect values could cause serious damage to the unit

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40010 Bentivoglio (BO)Via Romagnoli 12/aTel. 051/8908111Fax. 051/8908122

www.galletti.itCompany UNI EN ISO 9001 and OHSAS 18001 certified

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