GESTRA NRS 1-53 User manual

1
EN
English
Level Switch
NRS 1-53
Original Installation Instructions
819177-01

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Contents
Usage for the intended purpose ..............................................................................................................4
Function .................................................................................................................................................4
Safety note .............................................................................................................................................4
Important Notes
Page
Directives and Standards
VdTÜV Bulletin “Wasserstand 100” (= Water Level 100)..........................................................................5
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility) .......................................................5
ATEX (Atmosphère Explosible).................................................................................................................5
Note on the Declaration of Conformity / Declaration by the Manufacturer .........................................5
Dimensions NRS 1-53.............................................................................................................................8
Key.........................................................................................................................................................8
Installation in control cabinet ..................................................................................................................8
Name plate / marking .............................................................................................................................9
In control cabinet: Mounting level switch
Wiring diagram for level switch NRS 1-53.............................................................................................10
Key.......................................................................................................................................................10
Connecting supply voltage ....................................................................................................................11
Connecting MIN 1 / MIN 2 output contact..............................................................................................11
Connecting level electrode....................................................................................................................11
Tools.....................................................................................................................................................11
In control cabinet: Wiring level switch
Connecting several level electrodes ......................................................................................................12
Key.......................................................................................................................................................12
Examples of configuration NRS 1-53 / NRS 1-54, connection of several level electrodes.......................13
Connection of level electrode................................................................................................................14
In the plant: Wiring level electrode
NRS 1-53..........................................................................................................................................6 – 7
Scope of supply......................................................................................................................................7
Technical data

3
Contents - continued -
Page
Changing response sensitivity...............................................................................................................15
Checking switchpoint and function .................................................................................................16 ,17
Commissioning procedure
Indications and operation......................................................................................................................18
Operation, alarm and test
Factory settings
Factory setting......................................................................................................................................14
Protection against high frequency interference .....................................................................................19
Decommissioning / replacing the equipment ........................................................................................19
Disposal................................................................................................................................................19
Further notes

4
Important Notes
Usage for the intended purpose
The level switch NRS 1-53 in conjunction with level electrodes NRG 1.-.. and ER 5. is used as limit
switch, for instance in steam boiler and (pressurized) hot-water installations. The level switch detects
and indicates two low water levels (MIN 1, MIN 2).
The level switch NRS 1-53 can be used in combination with the following level electrodes:
Level electrodes
NRG 10-52,
electrode with
4 rods
NRG 16-52,
electrode with
4 rods
NRG 16-4,
electrode with
1 rod
ER 50,
electrode with
4 rods
ER 56,
electrode with
4 rods
The operation of the level switch NRS 1-53 is based on the conductive measuring principle using the
electrical conductivity of the water for signalling water level. The level switch is designed for different
electrical conductivities and for connecting two level electrodes.
If two electrode rods are associated and connected to the level switch, two different low water levels
(MIN 1 / MIN 2) can be detected and signalled. The length of the electrode rods determines the cor-
responding switchpoints.
As soon as the water falls below the preset low level (MIN 1 / MIN 2), the level switch detects that the
electrode rods are exposed. After the de-energizing delay the MIN 1 / MIN 2 output contact will be
switched over. At the same time the LEDs for MIN 1 and MIN 2 change from green to red.
Even if only one electrode rod is connected, both output contacts will be switched over after the de-
energizing delay and the LEDs change from green to red.
When the equipment is used as water level limiter, the safety circuit for the heating is opened by the
output contacts. The disconnection of the heating is interlocked in the external safety circuit and can
only be deactivated when the water level is sufficiently high.
By pressing the Test button, MIN 1 and MIN 2 alarms can be simulated.
Function
Safety note
The equipment fulfils a safety function and must only be installed, wired and commissioned by quali-
fied and competent staff.
Retrofitting and maintenance work must only be performed by qualified staff who - through adequate
training - have achieved a recognised level of competence.
Danger
The terminal strips of the equipment are live during operation.
This presents the danger of electric shock!
Always cut off power supply to the equipment before mounting, removing or connect-
ing the terminal strips!
Attention
The name plate specifies the technical features of the equipment. Note that any piece of
equipment without its specific name plate must neither be commissioned nor operated.

5
Directives and Standards
VdTÜV Bulletin “Wasserstand 100” (= Water Level 100)
The level switch NRS 1-53 in conjunction with level electrodes NRG 10-52, NRG 16-52,
NRG 16-4 and ER 5.-1 is type approved to VdTÜV Bulletin “Water Level 100”.
The VdTÜV Bulletin “Wasserstand (= Water Level) 100” specifies the requirements made on water level
control and limiting equipment for boilers.
ATEX (Atmosphère Explosible)
According to the European Directive 2014/34/EU the equipment must not be used in explosion risk areas.
Note
The level electrodes NRG 10-52, NRG 16-52, NRG 16-4 and ER 5.-1 are simple items of
electrical equipment as specified in EN 60079-11 section 5.7. According to the European
Directive 2014/34/EU the equipment must be equipped with approved Zener barriers if used
in potentially explosive areas.
Applicable in Ex zones 1, 2 (1999/92/EC).
The equipment does not bear an Ex marking.
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility)
The equipment meets the requirements of the Low Voltage Directive 2014/35/EU and the EMC Direc-
tive 2014/30/EU.
Note on the Declaration of Conformity / Declaration by the Manufacturer
For details on the conformity of our equipment according to the European Directives see our Declara-
tion of Conformity or our Declaration of Manufacturer.
The current Declaration of Conformity / Declaration of Manufacturer are available in the Internet under
www.gestra.com/documents or can be requested from us.

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NRS 1-53
Supply voltage
24 VDC +/– 20 %
Fuse
external 0.5 A (semi-delay)
Power consumption
2 VA
Connection of level electrode
2 inputs for level electrode NRG 10-52, NRG 16-52, NRG 16-4 and ER 5.-1,
4 poles with screen
Electrode voltage
5 VSS
Response sensitivity (Electrical conductivity of water at 25 °C)
> 0.5 ... < 1000 μS/cm or > 10 ... < 10 000 μS/cm (switch-selectable)
Outputs
2 volt-free change-over contacts, 8 A 250 V AC / 30 V DC cos ϕ= 1.
De-energizing delay: 3 sec.
Provide inductive loads with RC combinations according to manufacturer’s specification to ensure
interference suppression.
Indicators and adjustors
1 pushbutton “Test” for simulating MIN 1 / MIN 2 alarm,
2 red/green LEDs for indicating operating mode and MIN 1 / MIN 2 alarm,
1 green LED indicating “Power ON”,
1 code switch with 4 poles for changing the sensitivity
Housing
Housing material: base: polycarbonate, black; front: polycarbonate, grey
Conductor size: 1 x 4.0 mm² solid per wire or
1 x 2.5 mm2per stranded wire with sleeve to DIN 46228 or
2 x 1.4 mm2per stranded wire with sleeve to DIN 46228;
Terminal strips can be detached
Fixing of housing: Mounting clip on supporting rail TH 35, EN 60715
Electrical Safety
Pollution degree 2 for installation in control cabinet with protection IP 54, completely insulated
Protection
Housing: IP 40 to EN 60529
Terminal strip: IP 20 to EN 60529
Weight
approx. 0.2 kg
Technical data

7
NRS 1-53 - continued -
Ambient temperature
when system is switched on: 0 ° .... 55 °C, during operation: -10 ... 55 °C
Transport temperature
–20 ... +80 °C (< 100 hours), defrosting time of the de-energized equipment before it can be put into
operation: 24 hours.
Storage temperature
–20 ... +70 °C, defrosting time of the de-energized equipment before it can be put into operation:
24 hours.
Relative humidity
max. 95 %, no moisture condensation
Approvals:
TÜV certificate VdTÜV Bulletin “Water Lever 100”:
Requirements made on water level limiting & control equipment.
Type approval no. TÜV . WR/WB . XX-424
(see name plate)
Technical Data - continued -
Scope of supply
NRS 1-53
1 Level switch NRS 1-53
1 Installation manual

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1Upper terminal strip
2Lower terminal strip
Key
Installation in control cabinet
The level switch NRS 1-53 is clipped onto the support rail 4type TH 35, EN 60715 in the control
cabinet. Fig. 1
3Housing
4Supporting rail type TH 35, EN 60715
In control cabinet: Mounting level switch
Dimensions NRS 1-53
Fig. 1 2
74
1
4 3
46 120

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In control cabinet: Mounting level switch - continued -
Name plate / marking
Name plate (on top)
Name plate (at the bottom)
Type designation
Protection
Manufacturer
Output contacts
Fig. 2
Ambient temperature
External fuse for
output contacts
Material number
Supply voltage
Fuse, provided on site
Power consumption
Disposal note
Approvals
Connection of
level electrodes
Serial number
Safety note
Mat-Nr.: 392621
M 0,5A
24 V = +/- 20%
NRG 1.-.. ER 5.
2 VA
TÜV.WR/WB.xx-424
+
_
75
A
B
C
D
43 21
Folge - Typenschild
NRS 1-53
CorelDraw X3
Examiner
Designer
Drawer
Scale
Refer to protection notice ISO 16016!
Free size tolerance ISO 2768 mk 1:1
No Änderung/Modification Datum/Date Geänd/Modif. PrüferKonstr.
Datum/Date Name/Name
Nr./No
Ersatz für/Replaces Ersetzt durch/Replaced by
Ersteller/ Konstrukteur/ Prüfer/
Freimaßtoleranzen ISO 2768 mk
GESTRA
Schutzvermerk ISO 16016 beachten!
Maßstab/
Nr./ M-Nr.
- -
Laupichler
2012-03-21
2012-03-21 Paul
4-392704-01
42
01 TÜV-Nr.: die TÜV.WR/WB. 10-424 in 15-424 geändert 50000152O.HadréPaul2016-03-23

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In control cabinet: Wiring level switch
Wiring diagram for level switch NRS 1-53
5Connection of supply voltage 24 V DC with fuse 0.5 A (semi-delay) provided on site
6Reference electrode or vessel used as functional earth
7MIN 2 electrode rod or MIN electrode rod
8MIN 1 electrode rod
9Central earthing point (CEP) in control cabinet
0MIN 1 output contact
aMIN 2 output contact
bWire link, provided on site if only one electrode rod is used
Key
Fig. 3 5
9
(–) (+) 7
M 0.5 A
(semi-
delay) 8
6
a 0
b
0a
M 0.5 A
(semi-
delay) 6
7
9
5
(–) (+)

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In control cabinet: Wiring level electrode - continued -
Connecting supply voltage
The equipment is supplied with 24 V DC and fused with an external semi-delay fuse 0.5 A.
Please use a safety power supply unit with safe electrical isolation.
The power supply unit must be electrically isolated from dangerous contact voltages and must meet at
least the requirements on double or reinforced isolation according to one of the following standards:
DIN EN 50178, DIN EN 61010-1, DIN EN 60730-1 or DIN EN 60950.
Connecting MIN 1 / MIN 2 output contact
Wire the upper terminal strip 1(terminals 16-18, 21-23) according to the desired switching functions.
If only one electrode rod is used please connect the terminals 17 and 23 (safety circuit) and the termi-
nals 6 and 7 with a wire link. Fig. 3
Provide an external slow-blow fuse 2.5 A for the output contacts.
When used as water level limiter the level switch NRS 1-53 does not interlock automatically when the
water falls below the MIN level.
If an interlock function is required for the installation it must be provided in the follow-up circuitry
(safety circuit). The circuitry must meet the requirements of the EN 50156.
When switching off inductive loads, voltage spikes are produced that may impair the operation of con-
trol and measuring systems. Connected inductive loads must be provided with suppressors such as RC
combinations as specified by the manufacturer.
Connecting level electrode
To connect the level electrode(s) use screened multi-core control cable with a min. conductor size
0.5 mm2, e. g. LiYCY 4 x 0.5 mm2 , max. length: 100 m.
Wire terminal strip in accordance with the wiring diagram. Fig. 3.
Connect the screen only once to the central earthing point (CEP) in the control cabinet.
Make sure that connecting cables leading to the level electrodes are segregated and run separately
from power cables.
Tools
nScrewdriver for slotted screws, size 3.5 x 100 mm, completely insulated according to VDE 0680-1.
Attention
nDo not use unused terminals as support point terminals.

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In the plant: Wiring level electrode
Connecting several level electrodes
cLevel electrode NRG 10-52, NRG 16-52
with five-pole connector
dLevel electrode ER 5.., 4 pole connector
eLevel electrode ER 5.., 6 pole connector
Key
fLevel electrode NRG 16-4
g Central earthing point (CEP) in control cabinet
d
f
Fig. 4 Fig. 5
Fig. 6 Fig. 7
c
e
MIN 1
MIN 2 MIN 1
MIN 2
MIN 1
MIN 2
MIN 1
MIN 2
g g
g g
NRS 1-53 NRS 1-53
NRS 1-53 NRS 1-53

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In the plant: Wiring level electrode - continued -
Examples of configuration NRS 1-53 / NRS 1-54, connection of several level electrodes
e
Fig. 8
c
MAX
MIN
g
g
NRS 1-54NRS 1-53
g
NRS 1-53 NRS 1-54
Fig. 9
f
MIN
MIN
MAX
MIN
Fig. 10
NRS 1-53

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In the plant: Wiring level electrode - continued -
Connection of level electrode
The level switch NRS 1-53 can be used in combination with the following level electrodes:
Level electrodes
NRG 10-52,
electrode with
4 rods
NRG 16-52,
electrode with
4 rods
NRG 16-4,
electrode with
1 rod
ER 50,
electrode with
4 rods
ER 56,
electrode with
4 rods
To connect the level electrode(s) use screened multi-core control cable with a min. conductor size
0.5 mm2, e. g. LiYCY 4 x 0.5 mm2 , max. length: 100 m.
Wire terminal strip in accordance with the examples Fig. 4 to 10.
Check the connection of the screen to the central earthing point (CEP) in the control cabinet.
Attention
nPlease observe the instructions given in the installation & operating manual for the
NRG 10-52, NRG 16-52, NRG 16-4 and ER 5.-1!
nMake sure that connecting cables leading to the level electrodes are segregated and
run separately from power cables.
Factory settings
Level switch NRS 1-53
The level switch features the following factory set default values:
nResponse sensitivity: 10 μS/cm (at 25 °C)

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The terminal strips of the equipment are live during operation.
This presents the danger of electric shock!
Always cut off power supply to the equipment before mounting, removing or connecting
the terminal strips!
Danger
Changing response sensitivity
If the electrical conductivity of water is < 10 μS/cm at 25 °C change the response sensitivity as follows:
nCut off supply voltage.
nRemove lower terminal strip. Fig. 10
nInsert a screwdriver to the right and left between the terminal strip and the front frame.
nUnlock terminal strip on the left and right side. For this purpose move screwdriver in direction of
the arrow .
nRemove the terminal strip.
n Set switch S4 of code switch hto ON (= response sensitivity 0.5 μS/cm).
nRe-attach lower terminal strip.
nApply supply voltage. Equipment is restarted.
Commissioning procedure
Fig. 11
Fig. 12
h
Toggle switch, white
Attention
Do not change the code switch hsettings of S1, S2 and S3!
h

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Commissioning - continued -
Checking switchpoint and function
Start
Activity Display Function
Switch on supply voltage.
Water level between MIN and
MAX.
LED “Power” is illuminated.
LED MIN 1 / MIN 2 illuminated
green.
MIN 1 / MIN 2 electrode rods submerged or
MIN electrode rod submerged.
Checking switchpoint and function (if 2 electrode rods are connected)
Lower water level until it is
below MIN 1 level. MIN 1
electrode rod is exposed.
MIN 1 LED flashes red. De-energizing delay is running.
MIN 1 LED is illuminated red. Time delay elapsed, MIN 1 output contact 21/23
closed, 22/23 open.
Lower water level until it is
below MIN 2 level. MIN 2
electrode rod is exposed.
MIN 2 LED flashes red. De-energizing delay is running.
MIN 2 LED is illuminated red. Time delay elapsed, MIN 2 output contact 16/18
closed, 17/18 open.
Checking switchpoint and function (if 1 electrode rod is connected)
Lower water level until it is
below MIN level. MIN electrode
rod is exposed.
MIN 1 / MIN 2 LEDs are flashing
red. De-energizing delay is running.
MIN 1 / MIN 2 LEDs are illumi-
nated red.
Time delay elapsed, MIN 1 output contact
21/23 closed, 22/23 open, MIN 2 output contact
16/18 closed, 17/18 open.
TEST button
MIN 1 LED red/green
Fig. 12
MIN 2 LED red/green
LED “Power”

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Possible installation faults (only if 2 electrode rods are connected)
Status and indication Error Remedy
No function.
MIN and MAX LEDs are flashing
simultaneously.
MIN 1 electrode rod is longer
than MIN 2 electrode rod.
Check and change the electrical connection of
the level electrode.
Commissioning - continued -
Checking switchpoint and function - continued -
Possible installation faults
Status and indication Error Remedy
Water level below MIN 1/ MIN 2
switchpoint, MIN 1/ MIN 2 LED
are illuminated green.
Electrode rods are too long. Cut electrode rods to the length required for the
MIN 1 / MIN 2 switchpoint or
Electrode rod is too long. Cut electrode rod to the length required for MIN
switchpoint.
If installed inside the boiler: Up-
per vent hole in protection tube
does not exist or is obstructed.
Check installation of level electrode. Make sure
that the level in the protection tube corresponds
to the actual water level.
Water level between MIN and
MAX. MIN 1 / MIN 2 LEDs are
illuminated red.
Electrode rods are too short.
Replace level electrode and cut electrode
rod(s) to the length dictated by MIN 1 / MIN 2
switchpoint.
Electrode rod is too short. Replace level electrode and cut electrode rod to
the length dictated by MIN switchpoint.
The earth connection to the
vessel is interrupted.
Clean seating surfaces and screw in level elec-
trode with metallic joint ring. Do not insulate
the electrode with hemp or PTFE tape!
Electrical conductivity of the
boiler water too low. Change response sensitivity to 0.5 μS/cm
Upper vent hole flooded.
Check installation of level electrode. Make sure
that the level in the protection tube corresponds
to the actual water level.

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Operation
Activity Display Function
Water level between MIN and
MAX.
LEDs MIN 1 and MIN 2 are
illuminated green.
MIN 1 output contact 21/23 open, 22/23 closed.
MIN 2 output contact 16/18 open, 17/18 closed.
MIN 1 and MIN 2 alarm (if 2 electrode rods are connected)
Water level below MIN 1
switchpoint.
MIN 1 LED flashes red. De-energizing delay is running.
MIN 1 LED is illuminated red. Time delay elapsed, MIN 1 output contact 21/23
closed, 22/23 open.
Water level below MIN 2
switchpoint.
MIN 2 LED flashes red. De-energizing delay is running.
MIN 2 LED is illuminated red. Time delay elapsed, MIN 2 output contact 16/18
closed, 17/18 open.
MIN alarm (if 1 electrode rod is connected)
Water level below MIN
switchpoint.
MIN 1 / MIN 2 LEDs are flash-
ing red. De-energizing delay is running.
MIN 1 / MIN 2 LEDs are illumi-
nated red.
Time delay elapsed, MIN 1 output contact 21/23
closed, 22/23 open, MIN 2 output contact 16/18
closed, 17/18 open.
Operation, Alarm and Test
Indicators and adjustors
Testing MIN 1 / MIN 2 alarm
During operation:
Water level between
MIN and MAX
Press and hold down button
“Test”.
MIN 1 LED flashes red. De-energizing delay is running.
MIN 1 LED is illuminated red
for 3 sec. MIN 1 output contact 21/23 closed, 22/23 open.
MIN 1 and MIN 2 LEDs are
illuminated green for 1 sec.
MIN 1 output contact 21/23 open, 22/23 closed.
MIN 2 output contact 16/18 open, 17/18 closed.
MIN 2 LED flashes red. De-energizing delay is running.
MIN 2 LED is illuminated red
for 3 sec. MIN 2 output contact 16/18 closed, 17/18 open.
The test is finished. Release
button “Test”. Equipment
returns to operating mode.
Note: If you continue to hold down the Test button, a new test is started.
You can abort the test any moment by releasing the Test button.

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If faults occur that are not listed above or cannot be corrected, please contact our service centre or
authorized agency in your country.
Action against high frequency interference
Further Notes
nSwitch off supply voltage and cut off power supply to the equipment.
nRemove the lower and upper terminal strips. Fig. 11.
nRelease the white fixing slide at the bottom of the equipment and take the equipment off the
supporting rail.
Decommissioning / replacing the equipment
Disposal
For the disposal of the equipment observe the pertinent legal regulations concerning waste disposal.
High-frequency interference can be caused by out-of-phase switching operations. Should sporadic
failures or malfunctions occur take the following remedial actions in order to suppress interference:
nProvide inductive loads with RC combinations according to manufacturer’s specification to ensure
interference suppression.
nIncrease the distance to sources of interference.
nCheck the connection of the screen to the central earthing point (CEP) in the control cabinet.
nHF interference suppression by means of hinged-shell ferrite rings.
nMake sure that connecting cables leading to the level electrodes are segregated and run separately
from power cables.

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819177-01/02-2017cm (808848-01) · GESTRA AG · Bremen · Printed in Germany
GESTRA AG
Münchener Straße 77
28215 Bremen
Germany
Telefon [phone]
Telefax [phone]
E-mail [email protected]
Web www.gestra.de
Agencies all over the world: www.gestra.de