GESTRA LRGT 16-3n User manual

Original Installation &
Operating Manual
Conductivity Transmitter
LRGT 16-3n
LRGT 16-4n
LRGT 17-3n
850878-01
EN
English

2LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
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..................................................................................................................... 7
Improper use .................................................................................................................................................. 8
Basic safety information ................................................................................................................................ 9
Required personnel qualifications............................................................................................................... 10
Notes on product liability............................................................................................................................. 10
Function ........................................................................................................................................................ 11
Technical data .............................................................................................................................................. 13
Example name plate/identification.............................................................................................................. 16
Factory settings............................................................................................................................................ 19
Measuring ranges of the LRGT 1x-3n based on the setting of the “Sout” parameter................................. 19
Overall view .................................................................................................................................................. 20
LRGT 16-3n............................................................................................................................................. 20
LRGT 16-4n............................................................................................................................................. 20
LRGT 17-3n............................................................................................................................................. 20
Dimensions of the LRGT 16-3n .................................................................................................................... 22
Dimensions of the LRGT 16-4n .................................................................................................................... 23
Dimensions of the LRGT 17-3n .................................................................................................................... 24
Installation.................................................................................................................................................... 25
Additional notes for installation ................................................................................................................ 26
Example LRGT 16-3n............................................................................................................................... 27
Installation examples with dimensions....................................................................................................... 29
Conductivity measurement ...................................................................................................................... 29
Conductivity monitoring and continuous blowdown control ...................................................................... 30
Conductivity monitoring and continuous blowdown control via a separate level pot.................................. 31
Key Fig. 11 to Fig. 13 ............................................................................................................................... 32
Aligning the terminal box............................................................................................................................. 32
Functional elements............................................................................................................................. 33

3LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Contents
Electrical connection.................................................................................................................................... 34
Notes on electrical connection ................................................................................................................. 34
Connecting the 24 V DC power supply ..................................................................................................... 34
Connecting the actual value output (4-20 mA).......................................................................................... 34
Pin assignment of the M12 connector for non pre-wired control cables ................................................... 34
Bringing into service .................................................................................................................................... 35
Changing the factory settings if necessary............................................................................................... 35
Changing the cell constant....................................................................................................................... 38
Changing the temperature coefficient ...................................................................................................... 39
Using the “CAL” function.......................................................................................................................... 39
Using the “FiLt” feature............................................................................................................................ 40
Changing the scale of the 4-20 mA actual value output ........................................................................... 40
Changing the display unit (µS/cm or ppm)................................................................................................ 41
Manually initiating a display test .............................................................................................................. 41
Comparing the reading with the reference reading from a reliable sample ............................................... 42
Starting, operation and testing .................................................................................................................... 43
System malfunctions.................................................................................................................................... 46
Causes .................................................................................................................................................... 46
Indication of system malfunctions using error codes................................................................................ 47
Errors that do not provoke a shutdown..................................................................................................... 49
Checking installation and function ........................................................................................................... 50
Taking out of service/Disassembly.............................................................................................................. 51
Cleaning the measuring electrodes of the conductivity transmitter.......................................................... 52
Comparison of readings .......................................................................................................................... 52
Cleaning interval...................................................................................................................................... 52
Disposal ........................................................................................................................................................ 53
Returning decontaminated equipment........................................................................................................ 53
Declaration of Conformity; Standards and Directives................................................................................. 53

4LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Content of this Manual
Product:
■ Conductivity transmitter LRGT 16-3n
■ Conductivity transmitter LRGT 16-4n
■ Conductivity transmitter LRGT 17-3n
First edition:
BAN 850878-00/05-2022cm
© Copyright
All rights reserved. Any misuse, particularly reproduction and dissemination to third parties, is not permitted.
The General Terms & Conditions of GESTRA AG apply.
Scope of delivery/Product package
■ 1 x conductivity transmitter LRGT 1x-xn
■ 1 x sealing ring, D 33 x 39, form D, DIN 7603-2.4068, bright annealed
■ 1 x Installation & Operating Manual
Required accessories for LRGT 16-3n, LRGT 17-3n and LRGT 16-4n when installing for the first
time
■ 1 x cable jack, Phoenix Contact SACC-M12FS-5PL-SH

5LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
How to use this Manual
This Installation & Operating Manual describes how to correctly use LRGT 16-3n, LRGT 16-4n and
LRGT 17-3n conductivity transmitters. It applies to persons who integrate this equipment in 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
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

6LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Types of warning
DANGER
Warning of a dangerous situation that results in death or serious injury.
WARNING
Warning of a dangerous situation that may possibly result in death or serious injury.
CAUTION
Warning of a situation that may result in minor or moderate injury.
ATTENTION
Warning of a situation that results in damage to property or the environment.

7LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Specialist terms / Abbreviations
Here, we explain some abbreviations, specialist terms, etc., which are used in this Manual.
LRGT .. / LRR .. / URS .. / URB .. / SRL .. / etc.
Equipment and type designations of GESTRA AG.
SELV
Safety Extra Low Voltage
Operating point (of the system)
The operating point describes the operating parameters at which a system or boiler is operated in
the nominal range. In a pressurised steam boiler, for example, these parameters would be output, capaci-
ty, pressure and temperature.
The design data may be a lot more stringent, however.
A boiler that is operated at 10 bar and 180°C may be designed for a pressure of 60 bar and a tempera-
ture of 275°C, for example, which is not necessarily its operating point.
Usage for the intended purpose
LRGT 16-3n, LRGT 16-4n and LRGT 17-3n conductivity transmitters can be used as conductivity limiters
and continuous blowdown controllers to continually monitor conductivity in steam boiler and hot-water
installations. They present a linear profile of conductivity in a preset measuring range via a 4-20mA
current output.
■ The transmitter’s 4-20 mA actual value output can be used with a suitable conductivity controller, as a
continuous blowdown controller with MIN/MAX alarm, for example.
■ To ensure problem-free operation, pay attention to the requirements for water quality as
specified in the technical rules (TRD) and EN standards for steam plants.
■ The equipment may only be used within the admissible pressure and temperature ratings, see
“Technical data” on page 13 and “Example name plate/identification” on page 16.

8LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Usage for the intended purpose
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 proper use in all applications, 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: http://www.gestra.com
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.

9LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Basic safety information
Danger to life from scalding if the conductivity electrode is removed under pressure.
Steam or hot water can spurt forcefully out of the equipment.
■ Only remove the conductivity electrode at 0 bar boiler pressure.
Risk of severe burns when working on a conductivity electrodes that has not been
allowed to cool. The conductivity electrode becomes very hot during operation.
■ Always allow the conductivity electrode to cool.
■ Perform all installation and maintenance work only when the conductivity
electrode has been allowed to cool.
There is a risk of electric shock during work on electrical systems.
■ Always switch off the voltage to the system before performing connection work.
■ Check that the system is not carrying live voltage before commencing work.
Danger to life from a faulty LRGT 1x-xn conductivity 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 con-
ductivity 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
rods to hard impacts.
■ Before and after installation, check that the conductivity electrode is undamaged.
■ When bringing the conductivity electrode into service, check that it is not leaking.
Attempts to repair the equipment will lead to non-availability of the system.
■ The LRGT 1x-xn conductivity electrode may only be repaired by the manufacturer, GESTRA AG.
■ Only replace faulty equipment with identical equipment from GESTRA AG.

10 LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Required personnel qualifications
Activity Personnel
Integration in control system Specialist staff Plant designer
Installation/electrical
connection/bringing into service Specialist staff
The equipment may only be installed, wired
and brought into service by qualified and
competent staff.
Operation Boiler service technician Staff trained by the plant operator.
Maintenance work Specialist staff
Maintenance and conversions 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
The manufacturer cannot accept any liability for damages resulting from improper use of the equipment.
Basic safety information
A lack of proper maintenance and cleaning can result in damage to the conductivity
electrode and/or false measurement results and warning messages.
■ Once a year, check the conductivity electrode by performing reference measurements. If
the “CF” (cell constant) value of 003.0 is exceeded after recalibration, the warning message
“CF.Hi” will appear.
■ Adhere to the maintenance and cleaning intervals, see page 52.

11LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Function
The equipment measures the electrical conductivity of electrically conductive fluids, and converts the infor-
mation into a conductivity-dependent 4-20 mA current signal.
Measuring process of the LRGT 16-3n and LRGT 17-3n
LRGT 16-3n and LRGT 17-3n conductivity transmitters use the conductometric two-electrode measuring
process. A measuring current with a suitable frequency for the measuring range is introduced into the
fluid. This produces a potential gradient between the electrode and the measuring tube, which is analysed
as a measuring voltage.
Measuring process of the LRGT 16-4n
The LRGT 16-4n conductivity transmitter uses the conductometric four-electrode measuring process. It
consists of two current and two voltage electrodes. The current electrodes introduce a measuring current
with a fixed frequency into the fluid. This gives rise to a potential gradient between these electrodes. This
potential gradient is then picked up by the voltage electrodes and analysed as measuring voltage.
Temperature compensation of readings based on a reference temperature (25°C)
The electrical conductivity changes as a function of the temperature. In order to base the readings on a
reference temperature, an integrated resistance thermometer measures the temperature of the fluid. The
electrical conductivity is calculated from the measuring current and measuring voltage, and then based
on the reference temperature of 25°C through temperature compensation.
Compensation process
Based on a set temperature coefficient, the conductivity reading is corrected to form a linear character-
istic. The coefficient (default 2.1% per °C) is normally used for steam generating units with a constant
pressure. Conductivity is established for an ambient temperature of 25 °C.
The gradient is then verified at service pressure using a calibrated conductivity meter.
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.
These transmitters do not have any controlling or limiting functions.
Automatic self-test
An automatic self-test periodically monitors the safety and function of the conductivity transmitters and
measured value acquisition.
Faults in the electrical connection or electronic measuring equipment trigger a fault indication on the
display, and the current output is set to 0mA.

12 LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Function
Display and signals, see page 43 / 47 *
LRGT 1x-xn conductivity transmitters feature a green 4-digit, 7-segment display for showing readings,
status information and error codes. The operating status is indicated by one red and three green LEDs.
Behaviour when switched on *
The display alternately shows the software version, the type and then the measured conductivity.
Behaviour in normal operation (no faults) *
The display shows the measured conductivity value (4 digits), e.g. 1550, and converts this value into a
current signal from 4-20 mA, in accordance with the predefined measuring range (see page 40, Sout
parameter). When you select an appropriate measuring range, you can expect plausible measurement
signals immediately after installation.
Behaviour in the event of malfunctions *
The error state or malfunction is shown on the display by an error code, e.g. E.005. For more on error
codes, see page 47 / 48.
Every time there is a fault, 0 mA is output via the current output.
Fault indications are displayed based on their priority. Indications with higher priority are shown contin-
uously before those with low priority. If several indications need attention, the display does not alternate
between them.
Electrode faults cannot be acknowledged.
When a fault is corrected, the message disappears from the display, and the LRGT 16-3n,
LRGT 17-3n or LRGT 16-4n conductivity transmitter returns to normal operation.
Behaviour when performing the test function *
Initiating the test function by pressing the rotary knob on the LRGT 1x-xn causes the maximum output
current of 20 mA to be output. This enables you to check the effect of limit violation on connected diag-
nostic testers.
* The tables on page 43 ff. 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 36 ff.

13LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Technical data
Model and mechanical connection
■ LRGT 16-3n, LRGT 16-4n, LRGT 17-3n Thread G1 A, EN ISO 228-1, see Fig. 6, 7 and 8
Nominal pressure rating, admissible service pressure and temperature
■ LRGT 16-3n PN 40 32 bar (g) at 238 °C
■ LRGT 16-4n PN 40 32 bar (g) at 238 °C
■ LRGT 17-3n PN 63 60 bar (g) at 275 °C
Materials
■ Terminal box 3.2581 G AlSi12, powder-coated
■ Cover tube 1.4301 X5 CrNi 18-10
■ Measuring electrodes 1.4571 X6CrNiMoTi17-12-2
■ Electrode insulation PTFE
■ Screw-in body:
◆ Measuring tube/screw of
LRGT 16-3n, LRGT 17-3n 1.4571, X6CrNiMoTi17-12-2
◆ Spacer disc of
LRGT 16-3n, LRGT 16-4n, LRGT 17-3n PEEK
Available electrode lengths (do not shorten)
■ LRGT 16-3n, LRGT 17-3n 200, 300, 400, 500, 600, 800, 1000 (mm)
■ LRGT 16-4n 180, 300, 380, 500, 600, 800, 1000 (mm)
Temperature sensor
■ Resistance thermometer Pt1000
■ Fluid temperature measuring range 0 to 280 °C
Conductivity range at 25 °C
■ LRGT 16-3n, LRGT 17-3n 0.5 μS/cm to 6000 μS/cm, 0.25 to 3000 ppm *
◆ Preferred measuring range up to 1000 µS/cm
■ LRGT 16-4n 50 μS/cm to 10,000 μS/cm, 25 to 5000 ppm *
◆ Preferred measuring range from 500 µS/cm
* Conversion of µS/cm to ppm (parts per million): 1 μS/cm = 0.5 ppm
Measuring cycle
■ for 1 second

14 LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Technical data
Measurement quality (figures for value ranges between the on-site calibration points)
■ LRGT 1x-3n
Resolution for internal processing * Measurement error Linearity error
◆ Range 1: 0.5 µS - 10 µS 7% 2%
◆ Range 2: 10 µS - 250 µS 3% 2%
◆ Range 3: 250 µS - 2600 µS 3% 1%
◆ Range 4: 2600 µS - 21000 µS 3% 1%
■ LRGT 16-4n
Resolution for internal processing * Measurement error Linearity error
◆ Range 1: 10 µS - 100 µS 2% 2%
◆ Range 2: 100 µS - 2000 µS 2% 1.5%
◆ Range 3: 2000 µS - 50000 µS 2% 1 %
* Resolution for internal processing based on 15 bits with plus or minus sign (16 bits).
The above figures refer to the uncompensated conductivity.
Time constant “T” (measured using the two-bath process)
Temperature Conductivity
■ LRGT 16-3n, LRGT 17-3n 9 seconds 14 seconds
■ LRGT 16-4n 11 seconds 19 seconds
Temperature compensation
■ The temperature compensation process is linear and can be set via parameter tC, see page 39.
Supply voltage
■ 24 V DC +/-20%
Power consumption
■ Max. 7 W
Current input
■ Max. 0.35 A
Internal fuse
■ T2A (slow blow)
Safety cutout at excessive ambient temperature
■ The cutout takes place at an excessive ambient temperature of Tamb. = 75 °C
Electrode voltage
■ < 500 mV (RMS) at no load

15LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Technical data
Analogue output
■ 1 x actual value output 4-20 mA
■ Max. output load 500 Ω
■ M12 connector, 5-pole, A-coded
Indicators and controls
■ 1 x 4-digit green 7-segment display for showing readings and status information
■ 1 x red LED for indicating an error state
■ 3 x green LEDs for indicating the unit μS/cm / ppm and OK status
■ 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
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
■ LRGT 16-3n, LRGT 16-4n, LRGT 17-3n approx. 2.1 kg

16 LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Example name plate/identification
IP rating
Supply voltage
Disposal information
Protection class
Fig. 2
The date of production (quarter and year) is stamped on the screw-in body of each conductivity
transmitter.
Safety
note
Equipment designation
Equipment function
Current
approval
Manufacturer
Serial number
Admissible service pressure,
admissible temperature
Admissible ambient
temperature
Nominal pressure rating,
connection thread, material of
screw-in body
Measuring range
Data interface
Conformity mark
Measuring range
Power consumption

17LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Example name plate/identification
Fig. 3
The date of production (quarter and year) is stamped on the screw-in body of each conductivity
transmitter.
Safety
note
Equipment designation
Equipment function
Current
approval
Manufacturer
Serial number
Admissible service pressure,
admissible temperature
Admissible ambient
temperature
Nominal pressure rating,
connection thread, material of
screw-in body
Measuring range
Data interface
Conformity mark
Measuring range
IP rating
Supply voltage
Disposal information
Protection class
Power consumption

18
Example name plate/identification
The date of production (quarter and year) is stamped on the screw-in body of each conductivity
transmitter.
LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Safety
note
Equipment designation
Equipment function
Current
approval
Manufacturer
Serial number
Admissible service pressure,
admissible temperature
Admissible ambient
temperature
Nominal pressure rating,
connection thread, material of
screw-in body
Measuring range
Data interface
Conformity mark
Measuring range
IP rating
Supply voltage
Disposal information
Protection class
Power consumption
Fig. 3

19LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
Factory settings
LRGT 1x-xn conductivity transmitters are delivered ex works with the following settings:
Parameter Menu display Unit
Parameter values
LRGT 16-3n
LRGT 17-3n LRGT 16-4n
Cell constant CF 0.210
Temperature coefficient tC % / °C 002.1
Filter constant (damping) FiLt seconds 0025
Scale of current output Sout µS 0500 7000
Display unit Unit µS
Fig. 4
Measuring ranges of the LRGT 1x-3n based on the setting of the “Sout” parameter
With the LRGT 1x-3n, the lower measuring range is directly dependent on the setting of the
Sout parameter. If the parameter is set too high or is still at the factory setting (500 µS), the
error E.002 may appear on the display if the conductivity of the fluid is low. Please check the
parameter and adjust it if necessary.
Conductivity measuring ranges/
actual value output
Measuring ranges
(μS/cm at 25 °C)
Current output
(mA = µS/cm)
Set via the rotary knob on the
operating panel by the boiler man-
ufacturer service or by specialist
personnel authorised by the boiler
manufacturer.
Maximum output load for actual
value output: 500 ohms.
4 mA equals 20 mA equals
0.5 – 20 0.5 20
1.0 – 100 0.5 100
2.0 – 200 0.5 200
5.0 – 500 0.5 500
10.0 – 1000 0.5 1000
20.0 – 2000 0.5 2000
60.0 – 6000 0.5 6000

20 LRGT 16-3n, 16-4n, 17-3n - Installation & Operating Manual - 850878-01
OK
!
+
-
Overall view
Fig. 5
OK
!
+
-
A
B
C
D
F
J
LRGT 16-3n LRGT 16-4n
I
G
E
H
K
LRGT 17-3n
OK
!
+
-