GESTRA NRS 1-56 User manual

Original Installation &
Operating Manual
EN
English
Level Switch
NRS 1-56
850142-00

2NRS 1-56 - Installation & Operating Manual - 850142-00
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
Applicable directives and standards...........................................................................................................9
Improper use .................................................................................................................................................. 9
Basic safety notes ........................................................................................................................................ 10
Required personnel qualifications............................................................................................................... 10
Notes on product liability............................................................................................................................. 10
Function ........................................................................................................................................................ 11
Technical data .............................................................................................................................................. 12
Name plate/Identification NRS 1-56 ............................................................................................................ 14
Factory settings............................................................................................................................................ 14
Functional elements and dimensions.......................................................................................................... 15
Installing the NRS 1-56 level switch............................................................................................................ 16
Electrical connection safety notes............................................................................................................... 16
Wiring diagram for the NRS 1-56 level switch............................................................................................ 17
Electrical connection.................................................................................................................................... 18
Connecting the 24V DC power supply .....................................................................................................18
Connecting the output contacts................................................................................................................18
Connecting the level electrodes ...............................................................................................................18
Connection examples ................................................................................................................................... 19
Inlet control - various level electrodes connected..................................................................................... 19
Discharge control - various level electrodes connected............................................................................ 20
Changing the equipment settings................................................................................................................ 21
Changing the sensitivity and function....................................................................................................... 21
Configuring the function and sensitivity.................................................................................................... 22
Bringing into service - starting, switchpoints and function test................................................................ 23
Bringing into service - operation, testing.................................................................................................... 25

3NRS 1-56 - Installation & Operating Manual - 850142-00
Contents
System malfunctions.................................................................................................................................... 27
Causes ....................................................................................................................................................27
Indication of system malfunctions............................................................................................................28
Action against high-frequency interference..............................................................................................28
What to do in the event of system malfunctions......................................................................................... 29
Taking out of service.................................................................................................................................... 29
Disposal ........................................................................................................................................................ 29
Returning decontaminated equipment........................................................................................................ 29
EU Declaration of Conformity....................................................................................................................... 30

4NRS 1-56 - Installation & Operating Manual - 850142-00
Content of this Manual
Product:
Level switch
NRS 1-56
First edition:
BAN 850142-00/10-2019cm
You can find the latest Installation & Operating Manuals on our website:
http://www.gestra.com/documents/brochures.html
© 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 switch
NRS 1-56
 1 x Installation & Operating Manual

5NRS 1-56 - Installation & Operating Manual - 850142-00
How to use this Manual
This Installation & Operating Manual describes the correct use of the NRS 1-56 level switch. 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
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

6NRS 1-56 - Installation & Operating Manual - 850142-00
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.

7NRS 1-56 - Installation & Operating Manual - 850142-00
Specialist terms/Abbreviations
Here, we explain some abbreviations, specialist terms, etc., which are used in this Manual.
NRG .. / NRS ..
GESTRA equipment and type designations, see page 8.
SELV
Safety Extra Low Voltage

8NRS 1-56 - Installation & Operating Manual - 850142-00
Usage for the intended purpose
The NRS 1-56 level switch can be used in conjunction with various conductive level electrodes as an
interval level control system in pressurised steam and hot-water plants and in condensate and feedwater
tanks.
The NRS 1-56 level switch also indicates two alarm states, which can be configured as MIN and MAX.
Overview of possible unit combinations
Level switch Level electrode Version
NRS 1-56 NRG 1-52 4-rod electrode
NRS 1-56 4 x NRG 16-4 1-rod electrode
NRS 1-56 NRG 16-36 4-rod electrode
Fig. 1
Key to Fig. 1:
NRG = level electrode
NRS = level switch
To ensure the proper use of equipment for 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 the system components named
in Fig. 1 on our website:
http://www.gestra.com/documents/brochures.html

9NRS 1-56 - Installation & Operating Manual - 850142-00
Usage for the intended purpose
Applicable directives and standards
The NRS 1-56 level switch has been tested and approved for use in the scope governed by the following
directives and standards:
Directives:
 Directive 2014/68/EU Pressure Equipment Directive
 Directive 2014/35/EU Low Voltage Directive
 Directive 2014/30/EU EMC Directive
 Directive 2011/65/EU RoHS Directive
Standards:
 DIN EN 60730-1 Automatic electrical controls – Part 1:
General requirements
 EN 61326-1 Electrical equipment for measurement, control and laboratory use –
EMC requirements
Standards documents:
 VdTÜV Bulletin BP WASS 0100-RL
Requirements for water level control and limiting equipment
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.

10 NRS 1-56 - Installation & Operating Manual - 850142-00
Basic safety notes
There is a risk of electric shock during work on electrical systems.
 Always switch off the voltage to the equipment before performing work on the terminal
strips.
 Check that the plant is not carrying live voltage before commencing work.
Faulty equipment jeopardises plant safety.
 If the NRS 1-56 level switch does not behave as described on page 23, it may be faulty.
 Perform failure analysis.
 Only replace faulty equipment with identical equipment from GESTRA AG.
Required personnel qualifications
Activity Personnel
Integration in control system Specialist staff Plant designer
Installation/electrical connection/
bringing into service Specialist staff Electrician/installer
Operation Boiler service technician Staff trained by the plant operator
Maintenance work Specialist staff Electrician
Setup work Specialist staff Plant construction
Fig. 2
Notes on product liability
The manufacturer cannot accept any liability for damages resulting from improper use of the equipment.

11NRS 1-56 - Installation & Operating Manual - 850142-00
Function
The NRS 1-56 level switch measures using the conductivity principle and makes use of the electrical
conductivity of the water to do this.
The level switch is designed for different conductivities and for connection to four electrode rods in total.
The level switch functions as an interval level control system (inlet/discharge/switchable), and also indi-
cates when the water reaches two independent alarm states, which can be configured as MIN or MAX.
The switchpoints for water level control and for the MIN or MAX levels are determined by the length of the
respective electrode rods.
For water level control, the level switch recognises whether the electrode rods are immersed or out of the
water and, depending on which function is set, it switches the controller output contact, which then turns
the feedwater pump on or off, for example. The Pump LED lights up when the level switch has switched
the feedwater pump on, for example.
Behaviour in the event of MIN/MAX water level alarms
When the MIN or MAX water level is reached, the level switch recognises that the corresponding electrode
rod is immersed or no longer immersed. When the off delay has elapsed, the relevant Alarm 1/2 output
contact is switched. The alarm 1/2 LED simultaneously lights up red.
Alarm simulation
A button is pressed to begin a test sequence. During the test sequence, the MIN or MAX alarm is
simulated, see table on page 26.
Behaviour in the event of error messages
If faults occur in the level electrode and/or the electrical connection, the integrated relays are
de-energised.
Alarm and fault indications are displayed by LEDs, see page 28.

12 NRS 1-56 - Installation & Operating Manual - 850142-00
Technical data
Supply voltage
 24 V DC +/-20 %
Power consumption
 Max. 2 VA
Current input
 Max. 0.2 A
Required external fuse
 0.5 A M
Inputs for connecting level electrodes
 4 x inputs for level electrodes: NRG 10-52, NRG 16-52; NRG 16-36, NRG 16-4,
four-pin with shield
Electrode voltage
 5 Vss
Sensitivity (water conductivity at 25 °C)
Switchable
 > 0.5 μS/cm < 1000 μS/cm
or
 > 10 μS/cm < 10,000 μS/cm
Alarm 1/Alarm 2 outputs
 2 x volt-free relay contacts, contact material AgNi0.15, AgSnO2
 Maximum switching current - 8 A at 250 V AC / 30 V DC - cos ϕ= 1
 Inductive loads must have interference suppression (RC combination) as specified by the
manufacturer
Off delay of Alarm 1/2 outputs
 3 seconds, factory set.
Pump output
 1 x volt-free relay contact, contact material AgNi0.15, AgSnO2
 Maximum switching current - 8 A at 250 V AC / 30 V DC - cos ϕ= 1
 Inductive loads must have interference suppression (RC combination) as specified by the
manufacturer
Required external fuse for output contacts
 T2.5A

13NRS 1-56 - Installation & Operating Manual - 850142-00
Technical data
Indicators and controls
 1 x button for initiating the test function
 1 x multicolour “ON” LED (green/red) - for indicating the operating state and internal errors
 green = running
 red = power up, malfunction or internal error
 1 x red “Alarm 1” LED for indicating a MIN/MAX alarm
 1 x red “Alarm 2” LED for indicating a MIN/MAX alarm
 1 x green “Pump” LED for indicating the ON/OFF pump status
 1 x 4-pole code switch for setting the function and sensitivity
Protection class
 III Safety Extra Low Voltage
IP rating to EN 60529
 Housing: IP 40
 Terminal strips: IP 20
Electrical safety
 Degree of contamination 2 for installation in control cabinet with protection rating IP 54, fully insulated
Admissible ambient conditions
 Service temperature 0 °C – 55 °C (0 °C – 55 °C at power-on)
 Storage temperature - 20 °C – 70 °C *
 Transport temperature - 20 °C – 80 °C (< 100 hours) *
 Air humidity max. 95 %, non-condensing
* Only switch on after a 24-hour defrosting period
Housing
 Housing material: Lower section of black polycarbonate (glass-fibre reinforced), front of grey polycar-
bonate
 2 x 8-pole terminal strips, removable separately
 Max. cross-section per screw terminal:
 1 x 4.0 mm2solid, or
 1 x 2.5 mm2stranded with sleeve, or
 2 x 1.5 mm2stranded with sleeve
 Housing attachment: Mounting clip on support rail TH 35 (to EN 60715)
Weight
 Approx. 0.2 kg

14 NRS 1-56 - Installation & Operating Manual - 850142-00
Equipment
designation
Mains voltage/
power con-
sumption/re-
quired external
fuse
Mat-Nr.: 393365
4-393363-00
M 0,5A
24 V
± 20% 2 VA
TÜV.WR.xx-xxx
+
_
1
2
3
4
5
6
7
8
Alarm 2
Alarm 1
Pump 2
NRG 1.-..
Pump 1
Name plate/Identification NRS 1-56
Fig. 3
Factory settings
The NRS 1-56 level switch is delivered with the following factory default settings:
 Function: Inlet control
 Sensitivity: > 10 μS/cm at 25 °C
 Code switch setting: Sliding switch, white (1 = OFF, 2 = ON, 3 = OFF, 4 = OFF)
Configuring the function and sensitivity,
see page 22, Fig. 13.
19
20
Ta mb = 55°C(131°F)T
IP 40 (IP 20)
16
17
Alarm2
3 s
Alarm1
3 s
18
21
22
23
250 V~T2,5 A
See installation
instructions
Betriebsanleitung
beachten
Voir instructions de
montage
NRS 1-56
Pump/
Valve
GESTRA AG
Münchener Str.77
28215 Bremen
GERMANY
Niveauschalter
Level switch
Commutateur de niveau
Safety
note
Manufacturer
IP rating/protection class
Admissible ambient temperature
Inputs
wiring diagram
Serial number
CE marking Disposal information
The date of production is printed on the side of the equipment.
External fuse for output
contacts
Outputs wiring
diagram

15NRS 1-56 - Installation & Operating Manual - 850142-00
A Upper terminal strip
B Front membrane with LED, see page 23
C Lower terminal strip
D 4-pole code switch, for setting the function
and sensitivity
E Housing
F Support rail TH 35
Functional elements and dimensions
1
ON 234
567
234
19 20 21 2217 18
46
74
120
A
B
C
F
E
The code switch can be accessed by
removing the lower terminal strip.
Equipment settings,
see page 22.
Fig. 4
1
ON 234
D

16 NRS 1-56 - Installation & Operating Manual - 850142-00
Installing the NRS 1-56 level switch
The NRS 1-56 level switch snaps onto a TH 35 support rail in a control cabinet.
DANGER
There is a risk of electric shock during work on electrical systems.
 Switch off the voltage to the plant before you install the equipment.
 Check that the plant is not carrying live voltage before commencing work.
1. Switch off the voltage to the plant and secure the surrounding equipment in the control cabinet, if live,
so it cannot be touched.
2. Carefully press the unit onto the support rail until the holder clips into place.
Electrical connection safety notes
DANGER
Incorrectly connecting the level switch or any associated components
is a danger to plant safety.
 Connect the level switch and all associated components as shown
in the wiring diagram in Fig. 5 of this Manual.
 Do not use unused terminals as jumpers or support terminals.

17NRS 1-56 - Installation & Operating Manual - 850142-00
Wiring diagram for the NRS 1-56 level switch
Supply voltage
Fuse provided at the site
M0.5A
Pump 1 electrode rod
(pump OFF for inlet control)
Alarm 1 (MIN/MAX) electrode rodAlarm 2 (MIN/MAX) electrode rod
Fig. 5
17 18 19 20 21 22
234567
ZEP
24 V DC
–
+
M 0,5 A
Relay output
Alarm 2
Pump
output
contact Alarm 1
MIN/MAX MIN/MAX
ON/OFF
3 s 3 s
Pump 2 electrode rod
(pump ON for inlet control)
Functional earth
Tank or reference electrode

18 NRS 1-56 - Installation & Operating Manual - 850142-00
Electrical connection
Connecting the 24V DC power supply
 The NRS 1-56 level switch is supplied with 24V DC.
 A safety power supply unit that delivers a Safety Extra Low Voltage (SELV) must be used to supply the
equipment with 24V DC.
 Use an M0.5A fuse as an external fuse.
Connecting the output contacts
 Connect the outputs as shown in the wiring diagrams in Fig. 5.
 Only use the terminals specified in the wiring diagrams.
 Use a T2.5A fuse to protect the switching contacts.
Connecting the level electrodes
 Use a shielded, multi-core control cable with a minimum conductor size of 0.5 mm2,
e.g. LIYCY 5 x 0.5 mm2.
 Maximum cable length = 100 m.
 Route connecting cables separately from power cables.

19NRS 1-56 - Installation & Operating Manual - 850142-00
Connection examples
Inlet control - various level electrodes connected
Function Code switch setting
MIN/MAX alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm)
12345678
NRG 1.-52
43
21
Fig. 6
MIN1/MIN2 alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm)
12345678
NRG 1.-52
43
21
Fig. 7
MIN/MAX alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm) with 4 x NRG 16-4
12345678
NRG16-4
NRG16-4
NRG16-4
3
3
3
NRG16-4
3
Fig. 8
MAX (Alarm 1)
Pump OFF
Pump ON
MIN (Alarm 2)
Pump OFF
Pump ON
MIN 1 (Alarm 1)
MIN 2 (Alarm 2)
MAX (Alarm 1)
Pump OFF
Pump ON
MIN (Alarm 2)

20 NRS 1-56 - Installation & Operating Manual - 850142-00
Connection examples
Discharge control - various level electrodes connected
Function Code switch setting
MIN/MAX alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm)
12345678
NRG 1.-52
43
21
Fig. 9
MAX1/MAX2 alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm)
12345678
NRG 1.-52
43
21
Fig. 10
MAX alarm and pump (ON/OFF) / sensitivity (> 10 μS/cm) with NRG 16-36
12345678
NRG 16-36
87
56
Fig. 11
MAX (Alarm 1)
Pump ON
Pump OFF
MIN (Alarm 2)
MAX 2 (Alarm 1)
MAX 1 (Alarm 2)
Pump ON
Pump OFF
MAX1 (Alarm 1)
Pump OFF
Pump ON