GESTRA NRGT 26-2 User manual

Original Installation &
Operating Manual
EN
English
Level Transmitter
NRGT 26-2
in Non-Standard
Lengths
850973-00

2NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Contents
Content of this Manual................................................................................................................................... 4
Scope of delivery/Product package............................................................................................................... 4
How to use this Manual.................................................................................................................................. 5
Illustrations and symbols used...................................................................................................................... 5
Hazard symbols in this Manual...................................................................................................................... 5
Types of warning ............................................................................................................................................ 6
Specialist terms/Abbreviations...................................................................................................................... 7
Usage for the intended purpose..................................................................................................................... 8
Improper use .................................................................................................................................................. 9
Basic safety notes .......................................................................................................................................... 9
Required personnel qualifications............................................................................................................... 10
Notes on product liability............................................................................................................................. 10
Function ........................................................................................................................................................ 11
Technical data .............................................................................................................................................. 13
Example name plate/Identification.............................................................................................................. 16
Factory settings............................................................................................................................................ 17
Overall view of the NRGT 26-2 ..................................................................................................................... 18
Dimensions of the NRGT 26-2 ...................................................................................................................... 19
Preparing for installation ............................................................................................................................. 20
Installation.................................................................................................................................................... 21
Installing the NRGT 26-2.......................................................................................................................... 22
Sealing surface dimensions of the NRGT 26-2 ......................................................................................... 22
Example .................................................................................................................................................. 22
Installing two level electrodes in a flange by detaching a terminal box ..................................................... 23
Installing two level electrodes in a flange by detaching a terminal box ..................................................... 24
Installing two level electrodes in a flange by detaching a terminal box ..................................................... 25
Installation example with dimensions for the NRGT 26-2 .......................................................................... 26
Positioning the terminal box........................................................................................................................ 30
Functional elements of the NRGT 26-2........................................................................................................ 31
Electrical connection.................................................................................................................................... 32
Notes on electrical connection ................................................................................................................. 32
Connecting the 24V DC power supply ...................................................................................................... 32
Connecting the actual value output (4 – 20 mA)....................................................................................... 32
Pin assignment of the M12 connector for non pre-wired control cables ................................................... 32

3NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Contents
Bringing into service .................................................................................................................................... 33
Changing the factory settings if necessary............................................................................................... 33
Changing parameters when password protection is enabled.................................................................... 33
Calibration at the lower limit of the active measuring range “CAL.L” (0% calibration value) ...................... 36
Independent rapid calibration at a water level of > 25% of the active measuring range “CAL.P”............. 36
Calibration at the upper limit of the active measuring range “CAL.H” (100% calibration value)................. 37
Setting the filter constant “Filt”................................................................................................................ 37
Manually initiating a display test .............................................................................................................. 37
Viewing the software version and equipment type "InFo"......................................................................... 38
Enabling/disabling password protection ................................................................................................... 38
Checking the level display by raising or reducing the level ....................................................................... 39
Checking the safety function by initiating a test function.......................................................................... 39
Starting, operation and testing .................................................................................................................... 40
System malfunctions.................................................................................................................................... 43
Causes .................................................................................................................................................... 43
Indication of system malfunctions using error codes................................................................................ 44
Common application and usage errors..................................................................................................... 46
Checking installation and function ........................................................................................................... 48
Taking out of service/Disassembly.............................................................................................................. 49
Cleaning the measuring electrode of the level transmitter ........................................................................ 50
Cleaning interval...................................................................................................................................... 50
Disposal ........................................................................................................................................................ 50
Returning decontaminated equipment........................................................................................................ 50
Declaration of Conformity; Standards and Directives................................................................................. 51

4NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Content of this Manual
Product:
■ Level transmitter NRGT 26-2 in non-standard lengths
First edition:
BAN 850973-00/07-2023cm
© Copyright
All rights reserved. Any misuse, particularly reproduction and dissemination to third parties, is not permit-
ted. The General Terms & Conditions of GESTRA AG apply.
Scope of delivery/Product package
■ 1 x level transmitter NRGT 26-2 in non-standard lengths
■ 1 x sealing ring D 27 x 32, form D, DIN 7603-2.4068, bright annealed
■ 1 x Installation & Operating Manual
Required accessories for NRGT 26-2 when installing for the first time
■ Connecting cable, M12 A-coded, 5m, mat. no. 1508392
■ Connecting cable, M12 A-coded, 10m, mat. no. 1508394
■ Connecting cable, M12 A-coded, 30m, mat. no. 1508395
Optional accessories or refit
■ Cable jack M12 A-coded, mat. no. 52820

5NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
How to use this Manual
This Installation & Operating Manual describes the correct use of the NRGT 26-2 level transmitter. It
applies to persons who integrate this equipment into control systems, install, bring into service, operate,
maintain and dispose of this equipment. Anyone carrying out the above-mentioned activities must have
read this Installation & Operating Manual and understood its contents.
■ Read this Manual in full and follow all instructions.
■ Please also read the instructions for use of any accessories.
■ The Installation & Operating Manual is part of the product package. Keep it in an easily accessible
location.
Availability of this Installation & Operating Manual
■ Make sure this Installation & Operating Manual is always available to the operator.
■ If you pass on or sell the equipment to a third party, please also hand over the Installation & Operating
Manual.
Hazard symbols in this Manual
Danger zone/Dangerous situation
Danger of death from electric shock
Illustrations and symbols used
1. Action to be taken
2.
■ Lists
◆ Bullet points in lists
A Keys to illustrations
Additional
information
Read the relevant
Installation & Operating Manual
+
-
Press the rotary knob

6NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Types of warning
DANGER
Warning of a dangerous situation that will result in death or serious injury.
WARNING
Warning of a dangerous situation that may possibly result in death or serious injury.
CAUTIONCAUTION
Warning of a situation that may result in minor or moderate injury.
ATTENTION
Warning of a situation that will result in damage to property or the environment.

7NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Specialist terms/Abbreviations
Here, we explain some abbreviations, specialist terms, etc., which are used in this Manual.
NRGT .. / NRR.. / NRS.. / URS .. / URB .. / SRL .. / etc.
Equipment and type designations of GESTRA AG.
SELV
Safety Extra Low Voltage
Operating point (of the plant)
The operating point describes the operating parameters within which a plant or boiler is operated in its
nominal range. In a steam boiler, for example, these parameters would be output, pressure and tempera-
ture.
The pressure at the operating point does not have to match the design pressure, but is the same or lower.

8NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Usage for the intended purpose
Use as a water level controller
The NRGT 26-2 level transmitter can be used to continually measure the water level in steam boiler and
hot-water installations, or in condensate and feedwater tanks. In the calibrated measuring range from 0%
to 100%, the level transmitter makes up the linear profile of the 4 – 20 mA current output.
Influence of the monitored fluid
■ The NRGT 26-2 level transmitter can be used in fluids with different conductivity and in insulating
fluids. However, a conductivity of less than 100 μS/cm has a major influence on the measured ca-
pacitance, which is why it is extremely important to recalibrate the measuring range at the operating
point* when bringing into service, see page 36.
* Operating point of the plant, see page 7.
■ To achieve the best possible reproducibility and maintain high-quality measurements (see “Technical
data” on page 13), the sensor must be installed in a protective tube (see “Installation example with
dimensions for the NRGT 26-2” on page 26 ff.).
■ The dielectric constant of the monitored fluid may require an adjustment to the measurement
frequency, if it deviates significantly from that of the usual water (εr = 80). To do this, please contact
GESTRA AG Service.
Systems without SIL rating
In systems without a SIL rating, any controller, display unit or diagnostic tester with an input for a stand-
ard 4 – 20 mA signal can be connected.
To ensure the proper use of equipment during all types of use, please also read the Installation
& Operating Manuals for the system components used.
■ You can find the latest Installation & Operating Manuals for other system components on our
website:
www.gestra.com

9NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Improper use
There is a danger of death due to explosion if the equipment is used in potentially explo-
sive atmospheres.
Do not use the equipment in potentially explosive atmospheres.
Do not bring any equipment into service that does not have its own specific name plate.
The name plate indicates the technical features of the equipment.
Basic safety notes
Danger to life from scalding if the level electrode is removed under pressure. Steam or
hot water can spurt forcefully out of the equipment.
■ Only remove the level electrode at 0 bar boiler pressure.
Risk of severe burns if work is performed on a level electrode that has not been allowed
to cool down. The level electrode becomes very hot during operation.
■ Always allow the level electrode to cool.
■ Perform all installation and maintenance work only when the level electrode has been
allowed to cool down.
There is a risk of electric shock during work on electrical systems.
■ Always switch off the voltage to the plant before performing connection work.
■ Check that the plant is not carrying live voltage before commencing work.
Danger to life from a faulty NRGT 26-2 level electrode due to the sudden escape of hot
steam or hot water.
Shocks and impacts during transport or installation can result in damage to or leaks in the level
electrode, causing pressurised hot steam or hot water to escape through the pressure relief
hole.
■ To prevent damage during transport and installation, do not expose the electrode rod to
major shocks or impacts.
■ Before and after installation, check that the level electrode is completely undamaged and do
not install any damaged components.
■ Check that the level electrode is not leaking when bringing into service.
Attempts to repair the equipment will cause the plant to become unsafe.
■ The NRGT 26-2 level electrode may only be repaired by the manufacturer, GESTRA AG.
■ Only replace faulty equipment with identical equipment from GESTRA AG.

10 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Activity Personnel
Integration in control system Specialist staff Plant designer
Installation/electrical connection/
bringing into service Specialist staff
The unit is an item of equipment with a
safety function (EU Pressure Equipment
Directive) and may only be installed, electri-
cally connected and brought into service by
suitable, trained staff.
Operation Boiler service technician Staff trained by the plant operator.
Maintenance work Specialist staff
Maintenance and refits may only be
performed by authorised staff who have
undergone specific training.
Refits Specialist staff Persons trained by the plant operator to work
with pressure and temperature.
Fig. 1
Notes on product liability
We the manufacturer cannot accept any liability for damages resulting from improper use of the equip-
ment.
Required personnel qualifications

11NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Function
Measuring process
The NRGT 26-2 level transmitter uses the capacitance measurement principle and converts level data into
a level-dependent 4 – 20mA current signal. The 0 – 100% measuring range can be scaled by modifying
the effective length of the electrode rod.
Transmitter function
The transmitter function is the ability of the electrode to provide a scalable measuring range on the
4 – 20 mA current output interface and to make this available to one or more recipients for analysis.
Level transmitters do not have any controlling or limiting functions.
The level transmitters are installed on the inside of steam boilers, tanks or feed lines of hot-water instal-
lations. A protective tube provided on site keeps them functioning reliably (see page 26 “Installation
examples”).
Automatic self-test
An automatic self-test periodically monitors the safety and function of the level transmitters and meas-
ured value acquisition.
Faults in the electrical connection or electronic measuring equipment trigger an error message on the
display, and the current output is set to 0mA.
Operation in external level pots
If a level transmitter is installed outside the boiler in a level pot that can be shut off, the connecting pipes
must be flushed regularly.
If the steam pipe is ≥ 40 mm and the water pipe is ≥ 100 mm, installation is regarded as internal. In this
case, upstream monitoring of flushing processes is not required.
Indications and signals, see page 40 / 43 *
The NRGT 26-2 level transmitter features a green 4-digit, 7-segment display for showing readings, status
information and error codes. The operating status is indicated by a red and green LED.

12 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Function
Behaviour when switched on *
The display alternately shows the software version, the type and then the scaled level reading.
Behaviour in normal operation (no faults) *
The display shows the scaled level reading (3 digits + 1 decimal place), e.g. 050.3, and converts the level
data into a level-dependent current signal from 4–20mA.
The scale of the 0 – 100% measuring range is factory-set to maximum for the electrode
length used. Adjustment under operating conditions is essential and must be performed when
bringing into service.
Adjusting the measuring range when bringing into service
When bringing into service, the measuring range must be adapted to the sight glass level (on the steam
boiler), see page 36 - 37.
Behaviour in the event of faults *
The error state or malfunction is shown continuously on the display by an error code, e.g. E.005 (for error
codes, see pages 44 - 45).
Every time there is a fault, 0 mA is output via the current output.
Faults are displayed based on their priority. Indications with higher priority are shown conti-
nuously before those with low priority. If several indications need attention, the display does
not alternate between them.
Electrode faults cannot be acknowledged.
When the fault is corrected, the message disappears from the display and the NRGT 26-2 level
transmitter returns to normal operation.
* The tables on pages 41 - 42 clearly show the relationship between the equipment
status, the display and the status LEDS.
Setting parameters and changing factory settings
If necessary, you can adapt the electrode parameters to suit conditions at the plant. You can set parame-
ters and change factory settings using a rotary knob on the terminal box, see page 34 ff.

13NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Technical data
Model and mechanical connection
■ NRGT 26-2 Thread G¾ A, EN ISO 228-1, see Fig. 5
Nominal pressure rating, admissible service pressure and temperature
■ NRGT 26-2 PN 40 32 bar (abs) at 238°C
Materials
■ Terminal box 3.2581 G AlSi12, powder-coated
■ Cover tube 1.4301 X5 CrNi 18-10
■ Electrode rod insulation PTFE
■ Screw-in body 1.4571, X6CrNiMoTi17-12-2
Max. installed length at 238°C, all measurements in mm
■ NRGT 26-2
Max. installed length: 2260 2365 2470 2575 2680
Measuring range: 2100 2200 2300 2400 2500
Do not shorten the electrode rod.

14 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Technical data
Measurement quality
The information below applies to a compensated fluid conductivity range from 0.5–10000µS/cm based
on 25°C.
■ Reading error: ± 1% of set measuring range at the operating point
■ Resolution of reading on display: 0.1%
■ Resolution for internal processing: 15 bit
■ Resolution of 4 – 20 mA output: 15 bit
■ Sensitivity (minimum conductivity)
◆ Water ≥ 0.5 µS/cm (see page 8 “Influence of the fluid
to be monitored”)
Supply voltage
■ 24 V DC ± 20%
Power consumption
■ Max. 7 W
Current input
■ Max. 0.3 A
Internal fuse
■ T2A
Safety cutout at excessive temperature
■ Cutout occurs when an excessive temperature of 75°C is measured in the electrode tip
Analogue output
■ 1 x actual value output 4 – 20 mA, proportional to level, galvanically isolated
■ Maximum output load 500 Ω
■ M12 connector, 5-pole, A-coded
Indicators and controls
■ 1 x green 4-digit, 7-segment display for showing status information
■ 1 x red LED for indicating an error state
■ 1 x green LED for indicating OK
■ 1 x rotary knob IP65 with button for menu navigation and test function
Protection class
■ III Safety Extra Low Voltage (SELV)
IP rating to EN 60529
■ IP 65

15NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Technical data
Admissible ambient conditions
■ Service temperature: 0 °C – 70 °C
■ Storage temperature: - 40 °C – 80 °C
■ Transport temperature: - 40 °C – 80 °C
■ Air humidity: 10% – 95% non-condensing
Weight (dependent on length of electrode)
■ NRGT 26-2 approx. 2.9 kg (with 2100 mm measuring range)
Admissible installation positions
■ Vertical

16 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Example name plate/Identification
A
A
Betriebsanleitung beachten!
See installation instruction!
Vor dem Öffnen des Deckels
Gerät freischalten!
Before removing cover
isolate from power supplies!
Tamb = °C (°F)T
bar (psi)
°C (°F)
L/H=
Pmax
Tmax
Tamb
GESTRA AG
Münchener Str.77
28215 Bremen
Made in Germany
The date of production (quarter and year) is stamped on the screw-in body of the level trans-
mitter.
Fig. 2
1 Safety note
2 Equipment designation
3 Equipment function
4 Nominal pressure rating
5 Connection thread
6 Screw-in body material
7 IP rating
8 Maximum pressure and temperature ratings
9 Supply voltage
0Power consumption
!Measuring range
" Actual value output
%Mark of conformity
&Disposal information
/Manufacturer
(Protection class
)Material number + serial number
1
2
3
4 5 6 7
8
9 0
!
&
/
)
%
(
"

17NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Factory settings
The NRGT 26-2 level transmitter has the following factory settings:
Menu display Parameter values Unit
CAL.L variable 0% Raw value (hex)
approx. 50 mV
CAL.P variable 25% Raw value (hex)
CAL.H variable 100% Raw value (hex)
approx. 2.0 V
FiLt 0005 Seconds
PW oFF - - -
Fig. 3

18 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
OK
!
+
-
Overall view of the NRGT 26-2
Fig. 4
A Terminal box
B Operating panel with 4-digit LED display/
malfunction and status LEDs and rotary knob, see
page 40
C Cover screws M4 x 16 mm
D M12 connector, 5-pole, A-coded
F Seal seat for sealing ring
I Electrode
G Sealing ring D 27 x 32, form D, DIN 7603-2.4068,
bright annealed
E Cover tube (simplified view)
H Electrode thread
J Electrode rod insulation, PTFE

19NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Dimensions of the NRGT 26-2
Fig. 5 All lengths and diameters
in mm
OK
!
+
-
140
G ¾
Size 41
0
Nm
50 70 90
110
120 100 80 60
41
175
w = 70
26 237
1 338
20
Thermal insulation
provided at the site
Ø15
1 2
Max.
installed length
at 238 °C
Measuring
range
2260 2100
2365 2200
2470 2300
2575 2400
2680 2500

20 NRGT 26-2 in non-standard lengths - Installation & Operating Manual - 850973-00
Preparing for installation
If the equipment is to be installed outdoors, outside the protection of a building, environ-
mental influences may adversely affect function.
■ Pay attention to the admissible ambient conditions in the technical data,
see page 15.
■ Do not operate the equipment if the temperature is below freezing.
◆ At temperatures below freezing, use a suitable heat source (e.g. control cabinet
heater, etc.).
■ Connect all plant parts to a central earthing point to prevent equalisation currents in the
shielding.
■ Use a cover to protect the equipment from direct sunlight, condensation and
heavy rain.
■ Use UV-resistant cable ducts for routing the connecting cable.
■ Take further measures to protect from harmful environmental influences such as lightning,
insects and animals, and salty air.
You will need the following tools:
NRGT 26-2
■ Torque wrench (with size 41 open-ended spanner attachment), see page 19.