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iSave 21 Plus
Data sheet [de]
28 pgs3.15 Mb0
Operating guide
96 pgs12.21 Mb0
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Operating guide [es]
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Danfoss iSave 21 Plus Operating guide

Operating guide
Energy Recovery Device
iSave 21 Plus
Installation, Operation and Maintenance Manual
hpp.danfoss.com
Operating guide | iSave 21 Plus
Document information and copyright
Installation, Operation and Maintenance Manual. Original operating manual document.
Danfoss can accept no responsibility for possible errors in the manual and instructions. Danfoss reserves the right to alter its products without notice. This also applies to products already on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed. All rights reserved. Contents provided herein must neither be distributed, copied, reproduced, edited or processed for any other purpose, nor otherwise translated or published without Danfoss’ express written consent.
PUMP
Type iSave 21 Plus ERD Code no. 180BXXXX
Serial no. XXXXXX02-XXX
MADE IN DENMARK
Danfoss A/S, 6430 Nordborg, Denmark
Validity
This manual is valid for iSave 21 Plus
Code no. Serial no. 180F7015 XXXXXX02-XXX 180F7016 XXXXXX02-XXX 180F7017 XXXXXX02-XXX 180F7018 XXXXXX02-XXX
The serial number is referring to the Serial no. on the product label. The digits shown (02) indicate the version number of the pump. This document is only valid for ERD version 2 and upwards.
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Operating guide | iSave 21 Plus
Table of Contents
2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Target group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Manufacturer and customer service address . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 Country specific information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5.1 United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6 Additional technical documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Application range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4 Preferred system design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 Arrival inspection, handling and storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1 Arrival inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4.2 Return to the supplier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4.3 Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4.3.1 Centre of mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.4 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5 Outdoor storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
5 Technical data and design review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
5.1 Design details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
5.2 Sound level of the iSave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
5.4 Temperature and corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
5.5 Dimensions and weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
5.6 Electrical motor data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
5.7 How does the iSave work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.7.1 Pressure excharger function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
5.7.2 Booster pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5.7.3 Lubrication flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5.7.4 Mixing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5.7.5 How does the iSave work in an RO system? . . . . . . . . . . . . . . . . . . . . . . . .16
5.8 Seawater quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
5.8.1 Pre-filtration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
5.8.2 Air bubbles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
5.8.3 Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
5.9 Initial start up and flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
5.10 Initial start up and settings of safety equipment . . . . . . . . . . . . . . . . . . . . .18
5.11 Flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.12 CIP of Membrane cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
5.13 High pressure remains after shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . .19
5.14 Over-pressurisation caused by low pressure isolation. . . . . . . . . . . . . . . . . .20
5.15 Over-pressurisation caused by the high pressure pump . . . . . . . . . . . . . . . .20
5.16 Preferred system design and P&ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
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Operating guide | iSave 21 Plus
6 On-site installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.2 Installation and alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.3 Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.4 Piping and joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
6.5 Flexible couplings and flexible hoses . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6.6 Mounting of coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6.7 Mounting of bell housing on iSave . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6.8 Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6.9 Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
6.9.1 Electric motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
6.9.2 Speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
6.9.3 Starting torque on the iSave/ramping the electric motor . . . . . . . . . . . . . . .25
6.9.4 Torque overloads protection on the iSave . . . . . . . . . . . . . . . . . . . . . . . . .25
7 Commissioning, start-up and shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.1 Safety regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
7.2 Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
7.3 Commisioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
8 Service/Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1 Safety regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8.2 Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
8.3 Maintenance schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.4 Tool used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
9 Trouble-shooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
9.1 Safety regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
10 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.1 Start and stop procedures (180R9213). . . . . . . . . . . . . . . . . . . . . . . . . . . .31
10.2 Membrane cleaning of the RO system with iSave unit (180R9214) . . . . . . . . . . 37
10.3 Data sheet iSave 21 Plus - iSave 40 (521B1464) . . . . . . . . . . . . . . . . . . . . . .43
10.4 iSave part list (521B1459) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
10.5 Hose assembly and installation (180R9434) . . . . . . . . . . . . . . . . . . . . . . . .83
10.6 Operating- and maintenance instruction, electric motor (180R9230) . . . . . . . . 91
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Operating guide | iSave 21 Plus
2. Introduction
2.1 General
iSave is manufactured by Danfoss A/S, and is sold and marketed by a net of authorised distributors world wide.
This manual contains the necessary instruc­tions for the installation, operation and service of the iSave.
All personnel who are responsible for the operation and maintenance of the iSave unit must read and fully understand these instructions, especially the section “Safety” before:
• Transporting of the iSave unit.
• Lifting the unit.
• Installing the iSave unit on a frame.
• Connecting the iSave unit to the fluid system.
• Connecting the electrical motor and instrumentation.
• Commissioning the unit.
• Servicing the iSave unit, mechanics and electrics.
• Decommissioning the iSave unit.
2.3 Symbols
Indicates something to be noted by
NB!
the reader.
Indicates a situation which will or couldresult in damage to the iSave and its function.
Indicates a situation which will or could result in personal injury and/or damage to the iSave.
Electrical hazard. Indicates a high-voltage warning
Safety glasses required
Hearing protection required
Safety shoes required
Safety helmet required
Ensure that these instructions are always readily available to all personnel concerned.
2.2 Target group
This manual is intended for use by personnel with qualified training and experience in the operation and maintenance of a Sea Water Reverse Osmosis (SWRO) or Brackish Water Reverse Osmosis (BWRO) system.
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Operating guide | iSave 21 Plus
2.4 Manufacturer and customer service address
2.5 Country specific information
1.4.1 United Kingdom
Danfoss A/S DK-6430 Nordborg, Denmark Telephone: +45 7488 2222 Email: highpressurepumpss@danfoss.com Home page: hpp.danfoss.com
UK importer:
Danfoss Ltd. 22 Wycombe End HP9 1NB Beaconsfield United Kingdom
2.6 Additional technical documents
Document name Content
Datasheet Description of the technical data and
dimensions of the iSave
iSave parts list Sectional drawings, parts list and spare part
numbers.
Instruction: start and stop of the SWRO with iSave unit
Instruction: Membrane cleaning of RO system with
Description of how to start and stop the iSave in the preferred RO system set-up.
Description of how to clean the membranes in the preferred RO system set-up.
iSave unit Instruction:
Hose assembly and installation Operating and maintenance instructions,
electric motor
Guideline for Hose assembly and installation
Operating and maintenance instructions for the standard electric motor, delivered from Danfoss.
See also appendix 10
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Operating guide | iSave 21 Plus
3. Safety
3.1 General
The iSave must not be used for other purposes than those recommended and specified without first consulting your local iSave distributor.
This manual must be read and completely understood by the responsible specialist personnel prior to installation and commis­sioning. Use of this manual does not relieve opera­tion and maintenance personnel of the responsibility of applying normal good judgment in the operation and care of this product and its components.
This manual must be available to all person­nel concerned at the site at all time.
An iSave must always be installed and used in accordance with existing national and lo­cal sanitary and safety regulations and laws. It is the responsibility of the safety officer or the chief operator to assure compliance with all local regulations that are not taken into account in this manual.
• Improper installation can cause fatal injuries.
• The iSave must not operate outside the application range.
• During the initial start-up, slowly raise the pressure of the system and adjust the over-pressure protection equipment for proper limit settings.
• Make sure that the pressure is released from the iSave before the iSave is disconnected from any pipe or hose connections in the iSave.
• Make sure that the iSave can be drained without injuring anyone and without contaminating nearby equipment or the environment.
• Before intervening in the iSave/system, the power must be shut off and the starting device must be locked. When intervening in the iSave unit, follow the instructions for Service/Maintenance, chapter 8.
• A failure to follow the instructions can result in personal injury and/or damage to the iSave. It will also invalidate the warranty.
Electrical hazard
The iSave is a rotating machine that typically operates at high pressure.
Always wear suitable safety and lifting equipment when handling the iSave.
• Bolt the iSave properly to the base before start-up to avoid personal injury and/or damage to the iSave.
• The pipe connections to the iSave must be stress-free mounted, securely fastened to the iSave and well supported. Improper installation will or could result in personal injury and/or damage to the iSave.
• Proper installation and care of shutdown devices and over-pressure protection equipment is essential.
• All electrical installation work must be carried out by authorised personnel in accordance with EN60204-1 and/or local regulations.
• Install a lockable circuit breaker to avoid inadvertent starting. Protect th motor and other electrical equipment from overloads with suitable equipment.
• The electric motors must be supplied with adequate cooling ventilation.
• The iSave must never run dry. Dry running produces heat and will cause damage to internal parts.
• If the iSave does not function satisfactorily, contact your local iSave distributor.
Use of this manual does not relieve
NB!
operation and maintenance personnel of the responsibility of applying normal good judgment in the operation and care of this product.
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Operating guide | iSave 21 Plus
3.2 Intended use
The iSave is designed for use as energy recovery device in Sea Water Reverse Osmosis (SWRO) or Brackish Water Reverse Osmosis (BWRO) system. The iSave must not be used for other purposes than recommended and quoted for without consulting your local iSave distributor.
3.3 Application range
For application range see data sheet 521B1464 available in appendix 10.3.
Applications not suitable for the iSave can cause damages to the iSave unit, with risk of personal injury.
3.4 Preferred system design
Danfoss recommends building systems with a high degree of safety. The P&ID in chapter
5.16 shows the Danfoss preferred system design.
• It is always the system builders’ responsibility that the system design does not cause any form of hazard and are adapted to local regulations.
• Proper installation and care of shutdown devices and over-pressure protectio equipment is essential.
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Operating guide | iSave 21 Plus
4. Arrival inspection, handling and storage
4.1 Arrival inspection
The iSave is packed in a wood container with plugs in the port connections to protect the unit from damage during transport.
Remove all packing materials immediately after delivery. Immediately check the shipment for damage on arrival and make sure that the name plate/type designation is in accordance with the packing slip and your order.
In case of damage and/or missing parts, a report should be drawn up and presented to the carrier at once.
The identification label on the iSave states the specific type, the serial number and the code number of the iSave; see fig. below. The last three digits of the Serial No. indicate the week and year of production.
PUMP
Type iSave 21 Plus ERD Code no. 180BXXXX
Serial no. XXXXXX02-XXX
MADE IN DENMARK
Danfoss A/S, 6430 Nordborg, Denmark
4.3 Handling
• Personnel involved in lifting and transportation of the equipment must be trained in proper handling and safety procedures.
• Observe the local regulations regarding lifting.
• Use suitable, permitted lifting equipment.
• The iSave (set) could slip the lifting arrangement.
• Be aware of individuals located in the operation area while lifting the component.
4.2 Return to the supplier
Flush the iSave with clean water. Drain the iSave and plug the port connections with a cap/cover.
Pack the iSave into a suitable container and make sure that it is suitably fastened to the container.
Please contact your local authorised distributor or:
Danfoss A/S DK-6430 Nordborg, Denmark Telephone: +45 7488 2222 Fax: +45 7445 3831 Email: highpressurepumps@danfoss.com Homepage: hpp.danfoss.com
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Operating guide | iSave 21 Plus
Check the mass (weight) of the iSave unit. All parts weighing more than 20 kg must be lifted using lifting slings and suitable lifting
Secure lifting slings around the part of the iSave and the back of the electric motor. Make sure that the load is balanced before attempting the lift.
devices, e.g. an overhead crane or industrial truck. All iSave units weight more than 20 kg.
Once the lifting is done the lifting eye must be removed from the pump.
Never lift the iSave unit with only one fastening point. Incorrect lifting can result in personally injury and/or damage to the unit.
4.3.1 Centre of mass
604
Never lift the iSave in the bell housing.
Incorrect lifting can result in personally injury and/or damage to the unit.
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Operating guide | iSave 21 Plus
4.4 Storage
Each iSave is tested before shipment and therefore holds water. Storage temperature: 1 °C to +70 °C (33 °F to 158 °F) – provided that the pump is drained of fluid and stored “plugged”.
Frost protection is required at temperatures below 1°C. Danfoss recommends using DOWFROST from DOW Chemical Company
or Chillsafe mono propylene glycol from Arco Chemical Company.
If the iSave is protected against frost, the storage temperature can be: -40 °C to +70 °C (-40 °F to 158 °F)
• The iSave is NOT delivered frost-protected from the factory.
• Only remove caps from the openings of the iSave at the time of installation.
4.5 Outdoor Storage
For outdoor storage cover the iSave (set) with waterproof material.
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Operating guide | iSave 21 Plus
5.1 Design details5. Technical data and
design review
11
12
17
1
18
15
10 9
16
14
8
1212
1: 2” Victaulic connections 2: Shaft 3: Low pressure shaft seal 4: Port flange 5: Port plate 6: Valve plate
6
5
1
13
7: Cylinder drum 8: Port flange 9: Port plate 10: Pins 11: Van es 12: Port plate
6
7
5
1
4
2
3
1
13: Coupling 14: Adapter flange 15: Rotor 16: Stator 17: Port flange 18: Outlet flange
5.2 Sound level of the iSave
The noise level from the iSave including the electrical motor is 78 dB (A). Measurements according to EN ISO 20361. The test is made
It is therefore important that the iSave unit is mounted correctly on a frame with dampers to minimise vibrations and noise.
under following conditions:
1. iSave and electrical motor mounted on Danfoss base plate.
2. Baseplate is isolated from concrete ground by rubber vibration dampers.
3. Flexible hoses are used on high pressure and low pressure sides of the iSave.
4. Rotation speed 1,500 rpm
5. System pressure 60 barg and a booster pressure of 3 barg.
It is also strongly recommended to use high-pressure flexible hoses between the hard piping in the RO plant and the iSave. See “hose assembly and installation” in appendix 10.6. Alternative use multiple flexible Victaulic® couplings on the hard piping. The noise level is influenced by:
• The speed of the iSave. High speed
creates more noise than low speed.
• Rigid mounting of the iSave baseplate
Influences
Since the iSave is mounted on a base plate and connected to the electromotor by a bell housing, the noise level can only be determined for the complete unit (system).
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generates more noise than flexible mounting
• Pipe mounting directly to the iSave
increases the noise level compared to flexible hoses.
Operating guide | iSave 21 Plus
5.3 Materials
All critical parts of the iSave are made of super-duplex 1.4410/UN S32750 or the like. Non-critical parts that are not in contact with sea water are made of AISI 316. The shaft to the electrical motor is sealed by a standardised mechanical seal. For a detailed material/part overview see appendix
In order to minimise the risk of crevice corrosion, always flush the iSave according to the specified start/stop procedure.
5.4 Temperature and corrosion
The chart below illustrates the corrosive resistance of different types of stainless steel related to NaCl concentration and temperature.
Depending on the NaCl concentration, the fluid temperature must be between: +2 °C to +50 °C (+35.6 °F to 122 °F).
5.5 Dimensions and weights
For dimensions and weights please refer to the iSave datasheet. See appendix 10.3
5.6 Electrical motor data
See datasheet in appendix 10.3 and “Operating and Maintenance instructions, electric motor” in appendix 10.6
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Operating guide | iSave 21 Plus
5.7 How does the iSave work?
Figure 5.1 shows a section view of the iSave
The iSave consists of a rotating isobargic pressure exchanger and a positive displacement pump, also called booster pump. The rotation speed of the pressure exchanger and the pump is exactly the same, as they are driven by the same electric motor.
5.7.1 Pressure exchanger function:
The pressure exchanger consists of two port plates, one at the concentrate side and one at the seawater side. In between there is a rotor with several ducts that connect the concentrate side with the seawater side. The pressure exchanger transfers pressure from the high-pressure (HP) concentrate (HP in) to the low-pressure (LP) seawater coming from low-pressure feed pump (LP in). To separate the HP side from the LP side there is a sealing zone on both port plates. A single duct in the rotor is either on the HP side, or on the LP side or in the sealing zone. A single duct is never in contact with more than one zone at the time. When the rotor rotates a duct will go from the LP zone over the first sealing zone into the HP zone, and hereafter from the HP zone over the second sealing zone and back to the LP zone.
The flow through the HP side of the iSave is forced and controlled by the booster pump.
When the high-pressure concentrate is flowing into the iSave it pressurizes the sea water in the duct coming from “LP in”. The pressurized seawater is then pumped out of “HP out”. Just before the HP concentrate in the duct comes to the seawater port plate, the duct goes into the sealing zone and the flow in the duct stops. When the duct goes into the LP zone the concentrate water is de-pressurized. The (LP) seawater coming from the LP feed pump (LP in) forces the LP concentrate out of “LP out”. This pressure exchange process is repeated for each duct with every rotation of the rotor, and the ducts are thus continuously filling and discharging. The flow on the HP side and LP side of the iSave is nearly constant over time.
There is no physical barrier in the ducts between the concentrate and seawater. This means that there will be a small amount of mixing between the two liquids.
NB!
Fig. 5.1.
HP-out
Seawater side
LP-in
When the iSave is rotating the water always flows respectively from LP-in to HP-out, AND from HP-in to LP-out. However, if the feed flow into LP-in is higher than the flow
HP-in
Concentrate side
LP-out
into HP-in, some of the LP feed flow will flow directly to LP-out. When the iSave is not rotating the seawater can only run directly from LP-in to LP-out.
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Operating guide | iSave 21 Plus
5.7.2 Booster pump
The booster pump is a positive displacement pump, which means that the flow is controlled by the speed of the electric motor; e.g. if the rotation speed of the electric motor is raised by 10%, the flow will be 10% higher and vice versa. The required rpm can be calculated based on the “rated flow” of the particular iSave. See datasheet in appendix 10.3.
At low speeds you may hear some minor clicking sounds from the pump. This is normal and is caused by the pins in the vane pump.
5.7.3 Lubrication flow
To lubricate the moving parts in the pressure exchanger there is a well defined leak between the port plates and the rotor, as well as in the high pressure bearing between the pressure exchanger and the booster pump. This leak is typically called “lubricating flow”. The leaks go from the high pressure side to the low pressure side of the pressure exchanger, and from the booster pump to the low pressure side of the pressure exchanger.
5.7.4 Mixing
There is no physical barrier in the ducts between the concentrate and seawater. This means that there will be a small amount of mixing between the two liquids. Because the two liquids are in contact for a short amount of time, the mixing is relatively low. On the RO market the mixing rate is defined as “balanced flow” when HP-out is equal to LP-in. Experience from the market shows that the corresponding increase in membrane operating pressure is about 1 barg.
obtained when the energy loss on LP feed is equal to or less than the energy loss caused by the excess pressure at the membrane.
5.7.5 How does the iSave work in an RO system?
The figure below illustrates a typical flow path of an SWRO or BWRO with an iSave.
The high-pressure (HP) concentrate (7) flows to the low-pressure (LP) concentrate outlet (3). The LP sea water (2) flows to the HP sea water outlet (5). The rotor, moving between the high-pressure and low-pressure streams, removes the high-pressure concentrate (7) and replaces it with feed water (2). The flow rate on the HP sea water outlet (5) is controlled by the iSave alone. The flow rate on the LP concentrate outlet (3) is controlled by the sea water feed pump (1) and the back pressure valve. This means that changing the LP feed flow (2) will not affect HP outlet flow (5) and, vice versa, that changing the HP outlet flow (5) will not af­fect the LP outlet flow (3).
As LP sea water (2) is flushing the LP concentrate to LP outlet (3), it is essential that the flow on the LP inlet (2) is equal to or slightly higher than the HP inlet (7). Otherwise there will be an “under-flush” and higher mixing will occur in the HP outlet (5). This higher mixing will result in a slightly higher pressure at the membrane.
The customer can reduce mixing by over-flushing the LP feed with excess feed water. See figure below. Over-flushing means energy loss. Optimal over-flushing is
The booster pump integrated in the iSave must only overcome the pressure drop from the high-pressure outlet (5) to the high-pressure inlet (7).
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During the RO process operation, water is pumped into the HP-membrane feed (6) by the HP pump (4) and the iSave (5). Almost all water coming from the HP pump (4) penetrates the membranes (8). Only a slight amount of the water is used as lubrication flow in the iSave. The lubrication flow is measured as the difference between the HP pump flow rate (4) and the permeate flow rate (8). The resistance to permeate in the membrane pressurises the HP loop.
The isobaric pressure exchanger technology in an SWRO or BWRO change the HP concentrate into HP seawater that is feed into the HP membranes. The iSave energy recovery technology thus significantly reduces flow needed from the main HP pump (4). Overall energy consumption of a SWRO or BWRO plant using the iSave depends on the recovery rate.
The operator can change the recovery rate to optimise the RO system performance. Changing the recovery rate in an RO system equipped with iSave is easy. Using the VFD, change the speed of the iSave and thereby the flow in the HP flow rate. Then change the LP feed (2) flow to the iSave to minimise mixing and optimise energy consumption. Make sure that flow and pressure are within the rated parameter of the iSave in question.
5.8 Seawater quality
5.8.1 Pre-filtration
It is important that the incoming water is filtered properly to assure optimum service life of the iSave. A true graded density melt-blown depth filter cartridge rated at 3 μm is therefore recommended. Poor pre-filtration of the feed water will result in reduced service life of the iSave.
The iSave may request a different pre-filter of the seawater than the HP pump and other components in the RO system. As the various filters on the market differ greatly, Danfoss High Pressure Pumps recommends using cartridges with consistent, reliable performance and high efficiency, in which fibres are blown continuously onto a central support core. Danfoss High Pressure Pumps does not recommend cartridges requiring any type of binders or resins.
It is important with selection of a proper filter housing to ensure good cartridge end sealing. If there is a high risk of water by-pass it is recommended to use a second stage filter solution.
NB!
Filters can be purchased from Danfoss High Pressure Pumps.
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5.8.2 Air bubbles
Large bubbles in a pressurised RO system can result in damage to piping and equipment. All air must be bleed from both the LP and HP before the RO system is pressurised. Special consideration should also be given to air bubbles in feed flow, continuously fed into the HP pump and iSave.
5.8.3 Chemicals
The iSave should not be exposed to chemicals that will damage the RO membranes.
5.9 Initial start up and flushing
Prior to the initial start-up, all piping associated with the iSave unit should be thoroughly flushed to assure that no impurities enter the iSave. Inadequate pre-flushing will strongly affect the life of the iSave and may lead to its eventual breakdown.
It is recommended to disconnect all connections to the iSave and to thoroughly flush the piping before the iSave is connected to the inlet and outlet connections.
5.10 Initial start-up and settings of safety equipment
The high-pressure pump feed water into the high pressure line may be able to generate a pressure higher than the maximum allowable pressure in the system. There is thus a risk of personal injury and/or damage to the iSave.
Depending of the type and size of the feed pump of the RO system, this pump may be able to generate a pressure higher than the maximum allowable pressure in the LP system. There is thus a risk that the iSave or the LP equipment could be damaged by over-pressurisation.
To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to safeguard the HP and LP sides of the iSave and/or the RO system.
It is essential that the water used for the final pre-flush is pre-filtered to a level described in chapter 5.8
It is recommended to install temporary basket strainers at both inlets to the iSave during the initial start-up and commissioning.
Also see “Instruction for start and stop of the SWRO with iSave unit” in appendix 10.1.
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5.11 Flushing
RO membranes require periodic flushing to limit biological fouling. There are two types of flushing: feed water (Seawater) flush and fresh water (Permeate) flush. Regardless of the flush water used, the water must be pre-filtered to the level described in chapter 5.8. All parts of the iSave must be flushed, i.e. LP- and HP flow channels.
Feed water flushing is part of a normal shutdown sequence. After the HP pump has been stopped, the permeate and concen­trate production will continue until the high-pressure drops below the osmotic
pressure. Both the iSave and the LP seawater feed pump must run until the conductivity measured at point (7) and (3) are satisfac­tory. See also P&ID in chapter 5.16.
Fresh water flushing is performed before every extended shutdown of the RO plant. Permeate is simultaneously fed into the iSave at LP in (2), and either to the HP pump inlet (1) or through some other injection point such as the CIP connections or full flow cleaning connection. See also P&ID in chapter 5.16. Permeate may be produced during this flushing process.
Special attention should be given to
NB!
the pressure in the HP line (7) as the iSave may start to cavitate when it runs at high speed and the pressure in the HP line (7) drops below 3 bargs. This can be avoided by reducing the speed of the iSave to about 750 rpm and keeping the pressure in the HP line at the minimum of 3 barg. At this low pressure the iSave may only run for a maximum of 10 minutes.
5.12 CIP or membrane cleaning
The purpose of membrane cleaning is to reduce scaling and fouling in the membranes. For optimal performance specific chemicals are required, depending on the cause of the pollution. After chemical treatment the system must be flushed with fresh water.
The flush water coming out of the membranes may consist of a large amount of suspended inorganic particles. It is important to assure that these particles are not lead into the iSave. It is essential that the water used for the final pre-flush is pre-filtered to a level described in chapter 5.8. The iSave should not be exposed to chemicals that will damage the RO membranes
Also see instruction “Membrane cleaning of RO system with iSave unit” in appendix 10.2.
5.13 High pressure remains after
shutdown
The HP line of the RO system equipped with an iSave can remain pressurised for a long time after shutdown. Pressure decreases as water slowly leaks through the iSave. If more rapid system depressurisation is required, the system should be bled through a suit­able valve on the HP concentrate line.
Always check the pressure in the high-pressure lines before making service in the HP lines or pressurised equipment.
Failing to flush the iSave with fresh water before extended shutdowns may result in extensive biological growth and cause corrosion in the iSave and other equipment in the RO system.
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5.14 Over-pressurisation caused by low pressure isolation
If the low-pressure side of the iSave is blocked and the iSave is exposed to high-pressure, there is a risk that the iSave or the LP piping could be damaged by over-pressurisation.
To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to assure that the HP of the iSave is depressurised prior to the isolation of the LP side.
5.15 Over-pressurisation caused by the high pressure pump.
The HP pump may be able to generate a pressure higher than the maximum allowable pressure for the iSave or the system – particularly if the HP pump is a positive displacement pump, the pump will be able to generate extremely high levels of pressure.
To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to assure that the HP of the iSave is protected against excess pressure.
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Operating guide | iSave 21 Plus
5.16 Preferred system design and P&ID
VFD
Media filter
1
Filter 3 micron nominel
Fresh water
permeate flush
Filter
10 micron
PIPI
19
absolut
F
12
LP in
*
2
F
HP out
11
M
VFD
PI
PS
HP in
3
iSave
4
M
18
PS
PI
5
PS
13 14
6
Full flow cleaning
7
10
PI
PI
15
20
F
* Second stage filter: If recommended housing design and cartridges are not used, a second stage filter is required
Explanation of P&ID setup
• The pressure switch (3) must stop the iSave (11) and the high-pressure pump (4) at pressures lower than the minimum inlet pressure or higher than the allowable maximum pressure.
• The non-return valve (18) prevents the high pressure flow from the membrane to flow back through the HP pump and into the low pressure piping. This may occur when the high pressure pump stops.
• The pressure relief valve (6) protects the
• Inlet filters assure proper water quality. High quality water extends the service life of the whole system.
• It is important with selection of a proper filter housing to ensure good cartridge end sealing. If there is a high risk of water by-pass it is recommended to use a second stage filter solution.
• The pressure switch (13) must stop the iSave when the pressure is lower than the minimum inlet pressure or higher than the maximum pressure.
entire system against pressure overload and relieves the water if the pressure exceeds the maximum set pressure. If the high pressure pump is a positive displacement pump, the pump can
See “Start and stop” procedure, “Membrane cleaning” procedure instruction in appendices
10.1 and 10.2
build up a very high pressure that will exceed the mechanical strength of the membrane housing, pipes and other accessories.
• The valve (8) bleeds the air out of the system. The valve must be placed at the highest point in the system.
• The pressure relief valve (19) protects the low pressure pipes against pressure overload and relieves the water if the pressure exceeds the maximum allowable pressure.
17
Permeate
F
Flowmeter
8
9
16
28
CIP
27
Drain
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Operating guide | iSave 21 Plus
6. On-site installation
6.1 General
For safety instructions see chapter 3.1
6.2 Installation and alignment
The figure below illustrates the major iSave components. Fig. 1
Motor
Bolts
Flexible coupling
Bell housing
iSave
Base plate
Port connection
Support bracket (AISI 316)
The iSave is connected to the electric motor by the bell housing and a coupling. The bell housing is not suitable for bearing the weight of either the iSave or the motor. Both the iSave and motor must be supported without applying stress/load to the bell housing.
Danfoss provides the iSave with a baseplate and support brackets. Although the baseplate is of a sturdy design, it can flex or bend when it is bolted to the foundation. The baseplate thus requires a solid foundation such as concrete or rigid steel frame. The baseplate itself must be aligned to avoid bending caused by bolting to an uneven foundation.
A rigid foundation for the iSave assembly is important, and the iSave assembly must be bolted to the foundation.
Bolts
To reduce noise it is recommended to use resilient mounts between the baseplate and the foundation. Make sure that the bolts are properly locked and will stay locked over time.
An unlocked bolt can result in personal injury and/or damage to the iSave.
Misalignment of the base plate may cause stress and/or damage to the bell housing.
6.3 Orientation
The iSave can be mounted horizontally and vertically.
When mounted vertically, the electric motor must be placed above the iSave.
The bolts used must be of proper design and must be installed in accordance with the bolt manufacturer’s recommendations.
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6.4 Piping and joints
Piping material and schedule is of high importance. The strength of the Victaulic® connections is influenced by the material used for both the Victaulic® clamps and the hard piping. The hard piping and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations.
Hard piping to the iSave must be properly aligned to avoid stress on the iSave port connections. Pipe connections must be aligned as shown in the figures below. Don’t use the iSave as a strain for hard piping.
Misalignment of the hard pipes may place stress on the iSave port connection and may damage the iSave
The hard piping and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations. A failure to comply with this will or may result in personal injury and/or damage to the iSave.
Correct piping alignment Incorrect piping alignment
Incorrect piping alignment
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6.5 Flexible couplings and flexible hoses
The strength of the Victaulic® connections is influenced by the material used for both the Victaulic® clamps and hose couplings. The flexible hose and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations.
See also “Hose assembly and installation” in appendix 10.5
The flexible hose and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations. A failure to comply with this will or may result in personal injury and/or damage to the iSave.
6.6 Mounting of coupling
The figure below illustrates how to mount the flexible coupling between the iSave and to connect it to the electric motor.
Any axial and radial load on the shaft must be avoided.
A: Flexible coupling B: Bell housing C: Motor shaft
6.7 Mounting of bell housing on iSave
The figure below illustrates how to mount the bell housing on the iSave. Screw the 4 bolts through the bell housing and into the iSave and tighten them to 30 Nm.
6.8 Accessibility
With respect to the service and replacement of the complete iSave unit, it is recommended to maintain sufficient space around the unit.
The space must be sufficient enough to allow for safe lifting of the equipment, with no risk for personal injury and/or damage to the iSave.
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Operating guide | iSave 21 Plus
6.9 Drives
6.9.1 Electric motor
The iSave must only be driven by an electric motor.
Using anything other than an electric motor can lead to an irreparable fracture of the iSave’s internal parts.
6.9.2 Speed control
The rotation speed on the electric motor can be controlled by a VFD. The direction of rotation is engraved with an arrow on the iSave.
Checking the direction of rotation can be made by:
1. Looking at the fan in the end of the electric motor.
2. Removing the plug in the bell housing and watch the rotation of coupling.
3. Before assembly the iSave on the electrical motor, check the rotation of the shaft on the electrical motor.
It is required to use a VFD or a soft starter.
A minimum of 10 seconds is required when ramping up the speed from zero to maximum. Otherwise, the torque on the iSave will exceed the maximum limit and may lead to an irreparable fracture of the iSave’s internal parts.
6.9.4 Torque overloads protection on the iSave
The electric motor and iSave must always be protected against overload. Both at start-up and at continues operation the maximum torque on the iSave must be monitored.
The electric motor must be shut of if the maximum torque of the iSave exceeds the defined limit. The response time of the power shutoff to the iSave must be of maximum 1 second.
If more electric motors are powered by the same soft starter or VFD, each electric motor must be equipped with “torque limit equipment” to protect the iSave against overload.
Special attention has to be on NON PROTECTED – FREE ROTATING shaft on the electrical motor. Ignorance will or could result in personal injury.
• Running the iSave in the wrong direction for more than a few min­utes can cause un-intended wear on the iSave.
• If the electric motor is running at a lower speed, extra care must be taken to ensure that the electric motor is NOT overheated. External cooling may be necessary.
6.9.3 Starting torque on the iSave/ramp­ing the electric motor
Because of the inertia of the iSave internal parts and the fact that the iSave includes a positive displacement pump, the torque will exceed the maximum allowable torque for the iSave when the speed is not ramped up from zero to maximum.
Below are examples of equipment which can measure the load on the electric motor or limit the torque on the iSave.
1. VFD with integrated current monitoring relays.
2. External current monitoring relays.
3. Torque limiter coupling.
See also examples of “iSave overload protection” equipment in appendix 10.5
The electric motor and iSave must always be protected against overload. Otherwise, the torque will exceed the maximum limit and may lead to an irreparable fracture of the iSave’s internal parts.
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Operating guide | iSave 21 Plus
7. Commissioning, start-up and shutdown
7.1 Safety regulations
The operator ensures that all inspection and installation work is performed by authorised, qualified specialist personnel who are thoroughly familiar with the manual.
Before starting up the iSave and the high pressure pump, make sure that the following requirements are met:
• The iSave has been properly connected to the electric power supply and is equipped with all protection devices in accordance with EN60204-1.
• Check that all motor protections are properly set.
• All safety equipment, auxiliary equipment and connections required are proper connected and operational.
• Check all bolts in all connections
and in the foundation of the iSave and the pumps.
7.2 Support
Danfoss A/S offers commissioning and service at system manufacturer’s location. Rate quotes are offered upon request.
7.3 Commissioning
Before starting up the iSave and the high pressure pump make sure that the following requirements are met:
• All pipes are flushed, free from debris and full of water.
• The iSave has been bled and is full of water.
• At pressure lower than 10 bargs, check the system for leakage.
Slowly raise the pressure in the system and set all pressure switches to the correct limit and continually check all connections for leakage.
• Set pressure relief valve on both low and high pressure at the maximum system pressure.
• Check high pressure hoses for proper assembly and inspect for externa leakage for all connections.
• At low pressure, start the iSave and
check direction of rotation.
• Start the system according to the
“Start and stop procedure” instructions in appendix. 10.1
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Operating guide | iSave 21 Plus
8. Service/ Maintenance
8.1 Safety regulations
The operator ensures that all maintenance, inspection and installation work is performed by authorised, qualified specialist personnel who are thoroughly familiar with the manual.
Before intervening in the iSave/system;
• The power must be shut off and the starting device be locked.
• The pressure in the High Pressure lines must be drained to the Low Pressure side.
• The Water in all connected pipes must be drained.
Always use suitable safety and lifting equipment when handling the iSave, and follow the instructions in chapter 4.3
• When saftey equipment has been adjusted make sure that proper re-adjustment has been made before start-up.
• When the system is re-started after service and maintenance follow the instructions in chapter 7 and in “Start and stop procedures” in appendix. 10.1
8.2 Support
Danfoss A/S offers commissioning and service at the system manufacturer’s location. Rate quotes are offered upon request.
8.3 Maintenance schedule
The schedule of preventive maintenance below will help ensure that the iSave provides years of trouble-free performance.
One day after commissioning:
1. Re-check bolts in the foundation and the baseplate of the iSave and tighten the bolts to specified torque if necessary.
2. Visually inspect all pipe connections / couplings for external leakage.
3. Re-check bolts in all pipe connections / couplings and tighten the bolts to specified torque if necessar y.
4. Replace filters if necessary
5. Clean the filter housing and reinstall filters. Make sure no debris enters the system.
Three months after commissioning:
1. Re-check bolts in the foundation and the baseplate of the iSave and tighten the bolts to specified torque if necessary.
2. Re-check alignment of iSave
baseplate and iSave.
3. Visually inspect all pipe connections
/ couplings for external leakage.
4. Re-check bolts in all pipe connections / couplings and tighten the bolts to specified torque if necessary.
5. Replace filters if necessary.
6. Clean the filter elements and install the new filters. Make sure no debris enters the system.
7. Audibly inspect the iSave assembly. If there is irregular sounds or vibrations inspect the internals parts of the iSave and replace if necessary.
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Operating guide | iSave 21 Plus
8,000 hours of operation after commissioning:
1. Re-check bolts in the foundation and the baseplate of the iSave and tighten the bolts to specified torque if necessary.
2. Re-check alignment of iSave baseplate and iSave.
3. Visually inspect all pipe connections / couplings for external leakage.
4. Re-check bolts in all pipe connections / couplings and tighten the bolts to specified torque if necessary.
5. Replace filters if necessary.
6. Clean the filter elements and install the new filter. Make sure no debris enters the system.
7. Audibly inspect the iSave assembly. If there is irregular sounds or vibrations inspect the internals parts of the iSave and replace if necessary.
8. Visually inspect pump coupling and replace if necessary.
9. Audibly inspect the iSave assembly. If there is irregular sounds or vibrations inspect the internals parts of the iSave and replace if necessary.
10.Check power consumption and flow out of the iSave. If there is irregular performances inspect the internals parts of the iSave and replace if necessary.
11.Inspect and replace, if necessary, the vanes in the vane pump.
Dimensions of the vanes
iSave type iSave 21 Plus Original height (H) 27 mm Change when H is less than 26 mm Original length (L) 79.84 mm Change when L is less than 79.64 mm
Annually:
1. See above section: “8,000 hour of operation after commissioning”.
2. See “Operating- and maintenance instruction, electric motor” in appendix 10.6
Follow manufacturer’s recommendations for electric motor service and maintenance.
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Operating guide | iSave 21 Plus
9. Trouble-shooting
9.1 Safety regulations
The operator ensures that all inspection and installation work is performed by authorised, qualified personnel who are thoroughly familiar with the manual.
Before intervening in the iSave/system;
• The power must be shut off and the starting device be locked.
• The pressure in the high-pressure lines must be drained to low-pressure side.
• The water in all connected pipes must be drained.
The numbers in () correspond to the preferred system design and P&ID
Problem Possible cause Action VFD can’t start the iSave
at initial start-up.
VFD is not designed for con­stant torque.
Ramp-up settings in the VFD is not correct. VFD is tilting.
Choose a VFD that is designed for constant torque.
Set Ramp-up parameters correct.
Valve (9) is closed Open valve (9)
Torque on iSave too high during operation
Pressure in the HP line (5) is too high
Pressure difference from HP­out (5) to HP-in (10) is too high.
Start the iSave only when the pressure in the HP line is low.
Clean or change membranes.
Debris in the booster pump or iSave.
Wear in the booster pump or iSave.
Design of the basic plant doesn’t fit the performance of the iSave.
Permeate production is too low (17).
Valves (6), (7), (8) or (16) are leaking.
Repair or change valve.
Internal leakage in iSave Repair iSave HP pump flow (2) is to small Incorrect speed on the HP
pump. Check the HP pump and repair
if necessary.
Pressure on the mem-
Fouling on the membranes Clean the membranes
branes (5) is too high.
Mixing in the iSave is too high. Check flow on LP-in (12) and
adjust flow.
Flow out of the iSave is too low, causes a recovery rate
Check speed on iSave and change if necessary.
that is too high.
Booster pump in the iSave is worn out. Perform service on the VP.
Pressure on the mem­branes (5) is too low.
Valves (6), (7), (8) or (16) are leaking.
Repair or change valve (s).
Internal leakage in iSave Repair iSave HP pump flow (2) is too small Incorrect speed on the HP
pump. Check the HP pump and repair
if necessary.
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Appendices
Energy Recovery Device
iSave 21 Plus
Installation, Operation and Maintenance Manual
hpp.danfoss.com
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