Pentair FLECK 2750 NXT User guide

www.pentairaquaeurope.com
INSTALLER
MANUAL
FLECK
2750 NXT/NXT2
INDUSTRIAL

Installer manual Fleck 2750 NXT/NXT2 - Table of Contents
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Table of Contents
1 Generalities..................................................................................... 6
1.1 Scope of the documentation ....................................................................... 6
1.2 Release management ................................................................................. 6
1.3 Manufacturer identifier, product ................................................................ 6
1.4 Intended use................................................................................................ 7
1.5 Abbreviations used...................................................................................... 7
1.6 Norms.......................................................................................................... 7
1.6.1 Applicable norms ................................................................................................ 7
1.6.2 Available certificates........................................................................................... 8
1.7 Procedure for technical support................................................................. 8
1.8 Copyright and Trademarks ......................................................................... 8
1.9 Limitation of liability.................................................................................... 9
1.10 Scan & Service application.......................................................................... 10
2 Safety .............................................................................................. 11
2.1 Safety pictograms definition ....................................................................... 11
2.2 Serial label location..................................................................................... 12
2.3 Hazards........................................................................................................ 12
2.3.1 Personnel ............................................................................................................ 12
2.3.2 Material ............................................................................................................... 13
2.4 Hygiene and sanitization ............................................................................. 13
2.4.1 Sanitary issues .................................................................................................... 13
2.4.2 Hygiene measures............................................................................................... 13
3 Description ...................................................................................... 14
3.1 Technical specifications .............................................................................. 14
3.2 Performance flow rate characteristics....................................................... 16
3.3 Outline drawing ........................................................................................... 17
3.4 Components description and location ........................................................ 18
3.4.1 With NXT controller and AC motor ..................................................................... 18
3.4.2 With NXT controller and DC motor ..................................................................... 20
3.4.3 With NXT2 controller and DC motor ................................................................... 23
3.5 System regeneration cycle.......................................................................... 25
3.5.1 Downflow regeneration cycle (5-cycles operation) ............................................ 25
3.5.2 Filter cycle (3-cycles operation) ......................................................................... 27
3.6 Configurations for softener, no by pass and filter...................................... 29
3.6.1 Downflow softener .............................................................................................. 29
3.6.2 No by pass configuration..................................................................................... 29
3.6.3 Filter .................................................................................................................... 30

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4 System sizing................................................................................... 31
4.1 Recommended Injector/DLFC/BLFC-Valve configuration ......................... 31
4.2 Sizing a softener (single unit) ..................................................................... 31
4.2.1 Parameters to be considered ............................................................................. 31
4.2.2 Determining the required volume of resin ......................................................... 32
4.2.3 Resin exchange capacity and capacity of the unit .............................................. 33
4.2.4 Valve configuration.............................................................................................. 34
4.2.5 Cycle time calculation......................................................................................... 35
4.3 Salt amount definition ................................................................................. 37
4.4 Injector flow rates ....................................................................................... 37
4.4.1 1600 injectors ...................................................................................................... 38
4.4.2 1650 injectors ...................................................................................................... 39
4.4.3 1700/1710 injectors ............................................................................................. 40
5 Installation ...................................................................................... 41
5.1 Warnings...................................................................................................... 41
5.2 Safety notices for installation ..................................................................... 41
5.3 Installation environement ........................................................................... 41
5.3.1 General ................................................................................................................ 41
5.3.2 Water ................................................................................................................... 42
5.3.3 Electrical ............................................................................................................. 42
5.3.4 Mechanical .......................................................................................................... 43
5.4 Integration constraints................................................................................ 43
5.5 Valve connection to piping........................................................................... 44
5.5.1 Top-mounted valve installation .......................................................................... 44
5.6 Block diagram and configuration example................................................. 46
5.7 Regeneration flows ..................................................................................... 47
5.7.1 Single valve (System 4) ....................................................................................... 48
5.7.2 Multiple valves, parallel interlock system (System 5)........................................ 48
5.7.3 Multiple valves, parallel series regeneration system (System 6)...................... 48
5.7.4 Duplex alternating immediate system (System 7) ............................................. 49
5.7.5 Duplex alternating delayed system (System 8) (NXT2 only)............................... 50
5.7.6 Multiple valves, parallel system with standby unit (System9) .......................... 50
5.7.7 Multiple valves, system on-demand (System 14) ............................................... 51
5.8 Electrical connections................................................................................. 55
5.8.1 NXT controller connections ................................................................................ 56
5.8.2 NXT2 controller connections .............................................................................. 57
5.8.3 NXT controller connections for multiple valves ................................................. 58
5.8.4 NXT2 controller connections for multiple valves ............................................... 59
5.9 Bypassing .................................................................................................... 60
5.10 Drain line connection .................................................................................. 60
5.11 Overflow line connection............................................................................. 61
5.12 Brine line connection .................................................................................. 62

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6 Programming .................................................................................. 63
6.1 NXT controller ............................................................................................. 63
6.1.1 Display ................................................................................................................. 63
6.1.2 Commands .......................................................................................................... 64
6.1.3 Setting the time of the day .................................................................................. 64
6.1.4 Basic programming mode .................................................................................. 64
6.1.5 Master programming mode................................................................................ 66
6.1.6 Diagnostic............................................................................................................ 81
6.1.7 Resetting the controller...................................................................................... 84
6.2 NXT2 Controller........................................................................................... 85
6.2.1 Display ................................................................................................................. 85
6.2.2 Commands .......................................................................................................... 87
6.2.3 Time of day menu ................................................................................................ 88
6.2.4 Basic programming mode .................................................................................. 89
6.2.5 Master programming mode................................................................................ 91
6.2.6 Diagnostic............................................................................................................ 117
6.2.7 Resetting the controller...................................................................................... 122
7 Commissioning................................................................................ 124
7.1 Water filling, draining and waterproofness inspection .............................. 124
7.1.1 Activating a single valve system (System 4) ....................................................... 124
7.1.2 Activating a multiple valves system (Systems 5, 6, 7, 8, 9 and 14)..................... 125
7.2 Sanitization .................................................................................................. 125
7.2.1 Disinfection of water softeners........................................................................... 125
7.2.2 Sodium or calcium hypochlorite ......................................................................... 126
7.2.3 Electro chlorination............................................................................................. 126
8 Operation......................................................................................... 127
8.1 Display ......................................................................................................... 127
8.1.1 NXT controller ..................................................................................................... 127
8.1.2 NXT2 controller ................................................................................................... 127
8.1.3 LED status ........................................................................................................... 129
8.2 Recommendations ...................................................................................... 129
8.3 Manual regeneration................................................................................... 129
8.3.1 Manual delayed regeneration ............................................................................. 129
8.3.2 Immediate regeneration ..................................................................................... 130
8.3.3 To advance regeneration cycles ......................................................................... 130
8.3.4 To stop a regeneration (NXT2 only) .................................................................... 130
8.4 Operation during a power failure................................................................ 130
9 Maintenance .................................................................................... 131
9.1 General system inspection.......................................................................... 131
9.1.1 Water quality ....................................................................................................... 131
9.1.2 Mechanical Checks ............................................................................................. 131
9.1.3 Regeneration test................................................................................................ 132
9.2 Recommended maintenance plan .............................................................. 133
9.2.1 Valve used for softening...................................................................................... 133

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9.2.2 Valve used for filtration....................................................................................... 135
9.3 Recommendations ...................................................................................... 136
9.3.1 Use original spare parts...................................................................................... 136
9.3.2 Use original approved lubricants........................................................................ 136
9.3.3 Maintenance instructions ................................................................................... 136
9.4 Cleaning and maintenance.......................................................................... 136
9.4.1 First steps............................................................................................................ 136
9.4.2 Power head and/or motor replacement ............................................................. 137
9.4.3 NXT to NXT2 controller upgrade......................................................................... 140
9.4.4 NXT2 controller replacement ............................................................................. 142
9.4.5 Piston and/or seal and spacer kit replacement ................................................. 143
9.4.6 Micro-switches replacement .............................................................................. 145
9.4.7 Cams replacement.............................................................................................. 147
9.4.8 Injector cleaning.................................................................................................. 148
9.4.9 BLFC cleaning ..................................................................................................... 149
9.4.10 DLFC cleaning ..................................................................................................... 150
9.4.11 Valve on tank assembly....................................................................................... 151
10 Troubleshooting .............................................................................. 152
10.1 Error detection ............................................................................................ 152
10.2 Programming error..................................................................................... 154
10.3 Examples of error displayed ....................................................................... 155
10.3.1 NXT controller ..................................................................................................... 155
10.3.2 NXT2 controller ................................................................................................... 155
11 Spare parts and options................................................................... 157
11.1 Valve parts list............................................................................................. 157
11.2 Power head parts list .................................................................................. 158
11.3 Injector parts list ......................................................................................... 160
11.3.1 1600/1650 injector parts list ............................................................................... 160
11.3.2 1700/1710 injector parts list ............................................................................... 160
11.4 Brine valve parts list ................................................................................... 161
11.5 Safety brine valves list ................................................................................ 163
11.6 Safety brine valves 2310 parts list .............................................................. 163
11.7 Distribution systems parts list.................................................................... 164
11.8 Air checks list .............................................................................................. 165
11.9 Meters parts list .......................................................................................... 165
11.10 Meter cables & meter kits list .................................................................... 166
11.11 CE compliance parts list ............................................................................. 166
11.12 Other components list................................................................................. 166
12 Disposal........................................................................................... 168

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1 Generalities
1.1 Scope of the documentation
The documentation provides the necessary information for appropriate use of the product. It
informs the user to ensure efficient execution of the installation, operation or maintenance
procedures.
The content of this document is based on the information available at the time of publication. The
original version of the document was written in English.
For safety and environmental protection reasons, the safety instructions given in this
documentation must be strictly followed.
This manual is a reference and will not include every system installation situation. The person
installing this equipment should have:
• training in the Fleck series, NXT/NXT2 controllers and water softener installation;
• knowledge of water conditioning and how to determine proper controller settings;
• basic plumbing skills.
This document is available in other languages on https://www.pentairaquaeurope.com/product-
finder/product-type/control-valves.
1.2 Release management
Revision Date Authors Description
A 26.05.2020 BRY/FLA First edition.
B 25.08.2020 BRY/FI NXT2 programming change.
C 15.12.2020 BRY/FLA NXT2 electrical connection correction.
1.3 Manufacturer identifier, product
Manufacturer: Pentair International LLC
Avenue de Sevelin 18
1004 Lausanne
Switzerland
Product: Fleck 2750 NXT/NXT2

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1.4 Intended use
The device is intended for industry environment use only and it is purpose-built for water
treatment.
1.5 Abbreviations used
Assy Assembly
BLFC Brine Line Flow Controller
BV Brine Valve
CW Cold Water
DF Down Flow
DLFC Drain Line Flow Controller
HW Hot Water
Inj Injector
NBP No By Pass
PH Power Head
QC Quick Connect
Regen Regeneration
S&S Seals & Spacers
SBV Safety Brine Valve
SM Side Mounted
Std Standard
TC Time Clock
TM Top Mounted
UF Up Flow
1.6 Norms
1.6.1 Applicable norms
Comply with the following guidelines:
• 2006/42/EC: Machinery Directive;
• 2014/35/UE: Low Voltage Directive;
• 2014/30/UE: Electromagnetic compatibility;
• 2011/65/UE: Restriction of use of certain hazardous substances in electrical and electronic
equipment (RoHS);
• UNI EN ISO9001.
Meets the following technical standards:
• EN 55014-1;
• EN 55014-2;
• EN 61000-6-1;

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• EN 61000-6-2;
• EN 61000-6-3;
• EN 61000-6-4;
• EN 61010-1;
• EN 61000-3-2;
• EN 61000-3-3.
1.6.2 Available certificates
• CE;
• DM174;
• ACS.
Please find beside the certifications for some of our
product families. Please note that this list is not an
exhaustive list of all our certifications. In case of need
for more information please contact us.
1.7 Procedure for technical support
Procedure to follow for any technical support request:
1. Collect the required information for a technical assistance request.
ðProduct identification (see Serial label location [→Page12] and Recommendations);
ðDescription of the device problem.
2. Please refer to the Troubleshooting [→Page152]. If the problem persists contact your
supplier.
1.8 Copyright and Trademarks
All indicated Pentair trademarks and logos are property of Pentair. Third party registered and
unregistered trademarks and logos are the property of their respective owners.
© 2020 Pentair. All rights reserved.

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1.9 Limitation of liability
Pentair Quality System EMEA products benefit, under specific conditions, from a manufacturer
warranty that may be invoked by Pentair’s direct customers. Users should contact the vendor of
this product for applicable conditions and in case of a potential warranty claim.
Any warranty provided by Pentair regarding the product will become invalid in case of:
• installation done by a non-water-professional;
• improper installation, improper programming, improper use, improper operation and/or
maintenance leading to any kind of product damages;
• improper or unauthorized intervention on the controller or components;
• incorrect, improper or wrong connection/assembly of systems or products with this product
and vice versa;
• use of a non-compatible lubricant, grease or chemicals of any type and not listed by the
manufacturer as compatible for the product;
• failure due to wrong configuration and/or sizing.
Pentair accepts no liability for equipment installed by the user upstream or downstream of Pentair
products, as well as for process/production processes which are installed and connected around
or even related to the installation. Disturbances, failures, direct or indirect damages that are
caused by such equipment or processes are also excluded from the warranty. Pentair shall not
accept any liability for any loss or damage to profits, revenues, use, production, or contracts, or
for any indirect, special or consequential loss or damage whatsoever. Please refer to the Pentair
List Price for more information about terms and conditions applicable to this product.

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1.10 Scan & Service application
Scan & Service mobile application is the ideal support for the maintenance person in his daily
business. A simple scan of an identification (ID) label (1) present on the valve with a smartphone
gives an instantaneously access to all updated information related to the product, such as:
• valve’s and tanks detailed configuration;
• manuals;
• spare parts lists;
• troubleshooting recommendations;
• multi-lingual videos, detailing how to best service a part;
• informations about new products, latest technologies, novelties about the Blue Network
program, etc.
1. Download the application "Scan & Service" from or in a
smartphone(4).
2. Open the application "Scan & Service".
3. Scan the bleam(3) stuck on the valve(2).
4. Navigate to find information.

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2 Safety
2.1 Safety pictograms definition
DANGER
This combination of symbol and keyword indicates an imminently hazardous situation
that will result in serious or fatal injury if not avoided.
WARNING
This combination of symbol and keyword indicates a potentially hazardous situation
that can result in serious or fatal injury if not avoided.
CAUTION
This combination of symbol and keyword indicates a potentially hazardous situation
that can result in minimal or minor injury if not avoided.
Caution - material
This combination of symbol and keyword indicates a potentially hazardous situation
that can result in material damage if not avoided.
Prohibition
Mandatory advice to follow.
Mandatory
Applicable guideline, measure.
Info
Informative comment.

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2.2 Serial label location
Model
Part number
Electrical rating
Serial number
Production date
Production order
Mandatory
Ensure that the serial label and the safety labels on the device are completely legible
and clean!
If necessary, replace them with new labels in the same positions.
2.3 Hazards
All the safety and protection instructions contained in this document must be observed in order to
avoid temporary or permanent injury, damage to property or environmental pollution.
At the same time, any other legal regulations, accident prevention and environmental protection
measures, as well as any recognized technical regulations relating to appropriate and risk-free
methods of working which apply in the country and place of use of the device must be adhered to.
Any non-observation of the safety and protection rules, as well as any existing legal and technical
regulations, will result in a risk of temporary or permanent injury, damage to property or
environmental pollution.
2.3.1 Personnel
CAUTION
Risk of injury due to improper handling!
Only qualified and professional personnel, based on their training, experience and
instruction as well as their knowledge of the regulations, safety rules and operations
performed, are authorized to carry out necessary work.

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2.3.2 Material
The following points must be observed to ensure proper operation of the system and the safety of
user:
• be careful of high voltages present on the transformer (100 – 240V);
• do not put your fingers in the system (risk of injuries with moving parts and shock due to
electric voltage).
2.4 Hygiene and sanitization
2.4.1 Sanitary issues
Preliminary checks and storage
• Check the integrity of the packaging. Check that there is no damage and no signs of contact
with liquid to make sure that no external contamination occurred;
• the packaging has a protective function and must be removed just before installation. For
transportation and storage, appropriate measures should be adopted to prevent the
contamination of materials or the objects themselves.
Assembly
• Assemble only with components which are in accordance with drinking water standards;
• after installation and before use, perform one or more manual regenerations in order to
clean the media bed. During such operations, do not use the water for human consumption.
Perform a disinfection of the system in the case of installations for treatment of drinking
water for human use.
Info
This operation must be repeated in the case of ordinary and extraordinary
maintenance. It should also be repeated whenever the system remains idle for a
significant time.
Valid only for Italy
In case of equipment used in accordance with the DM25, apply all the signs and
obligations arising from the DM25.
2.4.2 Hygiene measures
Disinfection
• The materials used for the construction of our products meet the standards for use with
potable water; the manufacturing processes are also geared to preserving these criteria.
However, the process of production, distribution, assembly and installation, may create
conditions of bacterial proliferation, which may lead to odor problems and water
contamination;
• it is therefore strongly recommended to sanitize the products. See Sanitization [→Page125] ;
• maximum cleanliness is recommended during the assembly and installation;
• for disinfection, use Sodium or Calcium Hypochlorite and perform a manual regeneration.

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3 Description
3.1 Technical specifications
Design specifications/ratings
Valve body Brass
Rubber components EP or EPDM
Weight (valve with controller) 4.6 kg (max)
Recommended operating pressure 1.8 - 8.6 bar
Maximum inlet pressure 8.6 bar
Hydrostatic test pressure 20 bar
Water temperature std 1 - 43°C
Water temperature for HW volumetric 1 - 65°C (only with mechanical or electronical stainless
steel meter)
Water temperature for HW time clock 1 - 82°C
Ambient temperature 5 -40°C
Regeneration flow DF
Bypass of raw water during
regeneration:
Standard Yes
NBP version No
Flow rates (3.5 bar inlet - valve only - top mount)
Continuous service flow (Δp=1bar) 5.9 m3/h
Peak service flow (Δp=1.8bar) 7.5 m3/h
Cv* 6.8gpm
Kv* 5.9m3/h
Maximum backwash flow
(Δp=1.8bar)
5.6 m3/h
*Cv: Flow rate in gpm across the valve at a pressure drop of 1 psi at 60°F.
*Kv: Flow rate in m3/h across the valve at a pressure drop of 1 bar at 16°C.
Valve connections
Tank top mounted adapter 2½”- 8 NPSM
Inlet/Outlet 1" BSP female
Riser tube 1”
Drain line ¾” NPT
Brine line (1600/1650) ⅜"
Brine line (1700/1710) ½”

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Electrical
Controller operating voltage 24VAC for NXT / 24VDC for NXT2
Input supply frequency 50 or 60Hz
Transformer output voltage 24VAC for NXT / 24VDC for NXT2
Motor input voltage until March 2019 24VAC
Motor input voltage April 2019
onwards
24VDC with AC-DC inverter
Power consumption 35W for 1 powerhead / 60W for 2 powerheads
Controller protection rating IP22
Valve protection rating IP44
Power supply 230VAC for NXT / 100-240VAC for NXT2, 50/60Hz,60VA,
Class II
Transient overvoltages within the limits of category II
Pollution Degree 3
Temporary overvoltages must be limited in duration and in frequency.
Model without transformer
CAUTION
Risk of injury due to electrical shock!
A switch or circuit-breaker must be included in the installation, it must be suitably
located and easily reached, it must be marked as the disconnecting device for the
equipment.
The power must be achieved by a transformer in which the primary windings are
separated from the secondary windings by REINFORCED INSULATION, DOUBLE
INSULATION, or a screen connected to the PROTECTIVE CONDUCTOR TERMINAL.
It is required the installation of a fuse as overcurrent protection, it has to be positioned
between the system and the secondary of the transformer in the installation with the
following characteristics: V≥30VDC or VAC, Imax=5.0A(ES.5x205.0A) if used with 1
powerhead and V ≥ 30 VDC or VAC, Imax = 10.0A (ES. 10x20 10.0A) if used with 2
powerheads.
Environmental conditions
• Indoor use only;
• temperature from 5°C to 40°C;
• maximum relative humidity 80% for temperatures up to 31°C decreasing linearly to 50%
relative humidity at 40°C;
• mains supply voltage fluctuations up to ±10% of the nominal voltage.

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3.2 Performance flow rate characteristics
The graph shows the pressure drop created by the valve itself at different flow rates. It allows
predetermining the maximum flow rate going through the valve depending on the system settings
(inlet pressure etc). It also allows to determine the valve pressure drop at a given flow rate, and
therefore to evaluate the system pressure drop vs flow rate.
FLOW RATE VS PRESSURE DROP
(single valve)
Service
Backwash
Flow rate [m³/h]
Pressure drop [bar]

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3.3 Outline drawing

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3.4 Components description and location
3.4.1 With NXT controller and AC motor
Drain line
Brine line
Injector block
Inlet
Power head
Brine valve

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Micro-switches
AC motor
NXT controller
Piston
Camshaft
Diagnostic button
Status LED
Display
Regeneration button
Shift button
Setting button

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3.4.2 With NXT controller and DC motor
Info
As of April 2019, NXT valves are supplied with 24VDC motor. This motor is equipped
with an AC-DC converter allowing it to be powered with 24VAC or 24VDC. Therefore,
when used with NXT boards which require 24VAC power supply and therefore send
24VAC to the motor, the inverter will convert it into 24VDC.
Drain line
Brine line
Injector block
Inlet
Power head
Brine valve