GESTRA NRS 2-3 User manual

1
NRS 2-3
Installation Instructions 810414-02
Level Switch Type
NRS 2-3
GESTRA Steam Systems


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Contents
Usage for the intended purpose ..............................................................................................................4
Safety note ............................................................................................................................................4
Danger ...................................................................................................................................................4
Attention................................................................................................................................................. 4
ATEX (Atmosphère Explosible).................................................................................................................4
Important Notes
Page
Explanatory Notes
Scope of supply ......................................................................................................................................5
System description .................................................................................................................................5
Function .................................................................................................................................................5
Designs ..................................................................................................................................................5
Design “b”............................................................................................................................................ 10
Design “c”/“d”......................................................................................................................................10
Tools ....................................................................................................................................................10
Installation
Electrical Connection
Design “b”............................................................................................................................................ 11
Wiring diagram for design “b”...............................................................................................................11
Design “c”/“d”......................................................................................................................................12
Wiring diagram for design “c”/“d” ........................................................................................................12
Attention ..............................................................................................................................................12
Key to wiring diagram...........................................................................................................................13
NRS 2-3 .................................................................................................................................................6
Dimensions ............................................................................................................................................7
Technical Data
NRS 2-3 .................................................................................................................................................8
Key.........................................................................................................................................................9
Functional Elements

3
Danger .................................................................................................................................................14
Note .....................................................................................................................................................14
Checking wiring....................................................................................................................................14
Applying mains voltage .......................................................................................................................14
Adjusting switchpoint “Low Level”........................................................................................................14
Adjusting switchpoint “Pump ON”.........................................................................................................14
Adjusting switchpoint “Pump OFF”........................................................................................................ 14
Adjusting switchpoint “High Level” ....................................................................................................... 15
Note .....................................................................................................................................................15
Table switchpoints ................................................................................................................................ 15
Contents – continued –
Commissioning
Page
Danger .................................................................................................................................................16
Note .....................................................................................................................................................16
Correct switchpoints............................................................................................................................. 16
Check power ........................................................................................................................................16
Operation
Danger .................................................................................................................................................17
Fault finding list for troubleshooting......................................................................................................17
Operational Malfunctions
Declaration of conformity......................................................................................................................18
Annex

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Important Notes
Danger
The terminal strip of the NRS 2-3 is live during operation. This presents the danger of
electric shock.
Cut off power supply before inserting or removing the 19" slide-in unit and before carrying
out any installation or maintenance work.
Usage for the intended purpose
Use level switch NRS 2-3 only in conjunction with GESTRA level transmitter NRGT 26-1 for pump
control.
Safety note
The equipment must only be installed and commissioned by qualified and adequately trained per-
sonnel.
Maintenance and retrofitting must only be performed by entrusted personnel who – through adequate
training – have achieved a recognised level of competence.
ATEX (Atmosphère Explosible)
The equipment constitutes a simple item of electrical equipment as defined in DIN EN 50020
section 5.4. According to the European Directive ATEX 94/9/EC the equipment may only be used in
potentially explosive atmospheres if it is provided with approved Zener barriers.
Application in Ex zones 1, 2 (1999/92/EC). The equipment does not bear an Ex marking.
The suitability of the Zener barrier is certified in a separate document.
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.

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Scope of supply
NRS 2-3, design “b”
1 Level switch NRS 2-3
1 Mounting panel for installation
in control cabinets
1 Installation manual
Explanatory Notes
System description
The level switch type NRS 2-3 is an analogue electronic control instrument (pump control) for the
capacitance level transmitter type NRGT 26-1S.
In combination with this transmitter the equipment can signal the following levels:
High level, low level, level control unit on/off
and can be used as level controller for steam boilers and pressurized hot-water plants.
Function
The standardized input current signal is transformed by the resistor into a level-proportional voltage
and then preamplified. This voltage is fed to three voltage comparators V1, V2, V3 and compared with
adjustable reference voltages. Depending on the comparison result the relays will be (de)energized as
follows:
■If the level voltage across V1 is higher than the reference voltage, relay 1 is de-energized and the
red LED Dilluminated.
■If the level voltage across V3 is lower than the reference voltage, relay 3 is de-energized and the
red LED Ailluminated.
■If the level voltage across V3 is higher than the reference voltage, relay 3 is energized and the red
LED Aextinguishes.
V2 works as switching controller, e. g. for the boiler feed pump.
■If the level voltage across V2 is lower than the reference voltage, relay 2 will switch on the pump.
The yellow LED Bis illuminated.
The pump switches off in accordance with the adjusted hysteresis, which is adjustable over 1 % to
50 % of the level transmitter measuring range. Once the adjusted value is reached the relay 2 switches
off the pump and the green LED Cis illuminated.
Designs
Design “b”
19" slide-in unit to DIN 41494 part 5, installed on a mounting panel for installation in control cabinets
with screw-type terminals at the top and bottom.
Design “c”
19" slide-in unit with guide rails and 32 pole screw-type connector for the installation in 19" mounting
panels acc. to DIN 41494 part 5.
Design “d”
19" spare slide-in unit
NRS 2-3, design “c”
1 Level switch NRS 2-3
2 Guide rails
1 32 pole screw-type connector
1 Installation manual
NRS 2-3, design “d”
1 Level switch NRS 2-3
1 Installation manual

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NRS 2-3
Technical Data
Type approval no.
GL 99249-96HH
LR 98/20074
BV 10617/Bo
RINA No ELE/30298/2
KR HMB06190-MS002
DNV A-8394
Mains voltage
230 V ± 10 %, 50/60 Hz
115 V ± 10 %, 50/60 Hz (option)
24 V ± 10 %, 50/60 Hz (option)
Power consumption
5 VA
Input
4 – 20 mA (coming from level transmitter)
Output
3 volt-free relay contacts
Max. contact rating with switching voltages of 24 V, 115 V and 230 V AC: 4 A resistive,
0.75 A inductive at cos ϕ= 0.5.
Max. contact rating with a switching voltage of 24 V DC: 4 A
Service life of relay: 30x106switching cycles.
Limit value high level /low level
Continuously adjustable within measuring range of level transmitter
Switchpoints pump on/off
Continuously adjustable within 1 – 50 % of the measuring range of level transmitter
Indicators and adjustors
1 red LED “high level”, 1 red LED “low level”, 1 yellow LED “pump on”, 1 green LED “pump off”.
4 adjustors for high level /low level and pump on/off.
Protection
IP 10 to DIN EN 60529
Max. admissible ambient temperature
0 °C to +70 °C
Case
19" slide-in unit with front panel to DIN 41494 part 5 and rear 32 way Euro card connector to
DIN 41612 installed in a mounting panel or for installation in 19" mounting panel.
Front panel, mounting panel: aluminium
Wiring
Design “b”: screw-type terminal strips at the back of the mounting panel, max. conductor size 1.5 mm2
Design “c”: 32 pole screw-type connector at the back of the 19" mounting panel,
max. conductor size 1.5 mm2
Supply line to level transmitter: screened two-core cable, conductor size 0.5 mm2, max. cable length 150 m
Internal fuse
Glass cartridge fine-wire fuse M 0.05 A, 5 x 20, replaceable
Weight
approx. 0.8 kg

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NRS 2-3
MAX
MIN
OFF
ON
87 9 10 11 12 13 14 15
17
1665
4
3
2
1
Technical Data – continued –
Dimensions
Fig. 1
67.7
80
180
88
207
∅6
NRS 2-3
MAX
MIN
OFF
ON
169 45.3 (9TE)
128.5
(TE = division units)
(1 TE = 5.08 mm)

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IP 10
NRS 2-3
MAX
MIN
OFF
ON
87 9 10 11 12 13 14 15
17
1665
4
3
2
1
NRS 2-3
MAX
MIN
OFF
ON
Functional Elements
NRS 2-3
Fig. 2
K
L
J
F
E
A
B
C
D
I
H
MAX 95 %
MAX 70 ° C

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A LED “Low Level”
B LED “Pump on”
C LED “Pump off”
D LED “High Level”
E Adjustor for high level
F Adjustor for pump off
H Adjustor for pump on
I Adjustor for low level
J Fixing screws
K Screw-type terminal strip
L 32way Euro card connector
Functional Elements – continued –
Key

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Installation
Design “b”
1. Drill four holes into the mounting panel of the control cabinet.
2. Put level switch onto the mounting panel and align.
3. Insert matching screws and fasten.
Design “c”/“d”
1. Install guide rails and screw-type connector into 19" mounting panel.
2. Insert 19" slide-in unit into the guide rails until it hits the stop.
3. Fasten the fixing screws J.
Tools
■Screwdriver for slotted screws, size 2 mm, 5 mm, completely insulated to VDE 0680

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Electrical Connection
Design “b”
Wiring is effected via the two screw-type terminal strips.
Use screened two-core cable, conductor size 0.5 mm2, max. cable length 150 m for the supply of the
level transmitter.
Wiring diagram for design “b”
4
3
2
5
1
Fig. 3 Example of fill control with second level indicator
G 2.5 A

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Electrical Connection – continued –
Design “c”/“d”
Wiring is effected via the 32 pole screw-type connector.
Use screened two-core cable, conductor size 0.5 mm2, max. cable length 150 m for the supply of the
level transmitter.
Wiring diagram for design “c”/“d”
4
3
2
5
1
Fig. 4
Attention
■Protect the control circuit with a 2.5 A (slow blow) fuse.
■Connect screen only to the assigned terminal of the switch.
■The screen must not make any other electrical contact.
■When switching off inductive loads, voltage spikes are produced that may impair
the operation of control and measuring systems. Inductive loads should therefore be
provided with commercial arc suppressor RC combinations, e. g. 0.1 µF/ 100 Ω.

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1 Level transmitter, output 4 – 20 mA
2 High level
3 Water level controller (fill control)
4 Low level (LED red/green)
5 Connection for another device, e. g. NRR 2-3
Key to wiring diagram
Electrical Connection – continued –

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Commissioning
1. Switch on the mains supply and verify that the NRS 2-3 is receiving power. The LED Bor Cwill
illuminate to verify this.
1. Make sure that the 19" slide-in unit has been properly installed in the mounting panel.
2. Make sure that the mains supply corresponds to the wiring carried out on the equipment.
Checking wiring
Applying mains voltage
Danger
The terminal strip of the NRS 2-3 is live during operation. This presents the danger of
electric shock.
Cut off power supply before removing or inserting the 19" slide-in unit or undertaking any
kind of installation or maintenance work.
1. Fill the tank and observe the level indicator until the water has reached the desired level.
2. Turn the adjustor Ifrom the left stop slowly to the right just until the red LED Alights up.
Adjusting switchpoint “Low Level”
1. Raise the water level in the tank until the desired switchpoint for the feedpump is reached.
2. Turn the adjustors Fand Hto the left stop.
3. Turn the adjustor Hfrom the left stop to the right until the yellow LED Blights up.
4. Turn the adjustor Fto the right stop. The green LED Cis not illuminated.
Adjusting switchpoint “Pump ON”
Note
The level switch NRS 2-3 can only be operated and checked in combination with the
level transmitter NRGT 26-1S.
1. Raise the water level in the tank until the desired switchpoint for the pump is reached.
2. Turn the adjustor Fto the left until the green LED Cpump off lights up.
3. Carry out a final adjustment during operation: Adjust Fsuch that the exact switchpoint is achieved.
Turning to the right increases the distance between the pump on and pump off positions.
Adjusting switchpoint “Pump OFF”

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Commissioning – continued –
1. Fill the tank until the max. admissible water level is reached.
2. Turn the adjustor Efrom the right stop slowly to the left until the red LED Dlights up.
Adjusting switchpoint “High Level”
Mark the adjusted switchpoints either on the water level indicator and/or enter the data into the
following table:
Switchpoint (above the lowest water level)
Low level ...................... mm
Pump on ...................... mm
Pump off ...................... mm
High level ...................... mm
Table switchpoints
Note
You can directly change the switchpoints over the whole measuring range of the level
transmitter by using the adjustors Ifor low level, Hfor pump on and Efor high level.
To avoid confusion of the switchpoints during commissioning, we recommend that the
above-mentioned sequence is carefully followed.
The adjustor Ffor pump off is for changing the distance to the switchpoint pump on only.

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Operation
1. Check the measuring current coming from the level transmitter across the terminals 5(+) and 6(–)
in the case of design “b” and A22/C24 in the case of design “c” and “d”.
Measuring current: 4 to 20 mA
During operation you have to correct the switchpoints if the following malfunctions occur:
■Pump is switched on and off too frequently
Increase the distance between the switchpoints pump on and pump off. Turn the adjustor Fto the
right.
■ Signal low level too frequently
Raise the switchpoint pump on or lower the switchpoint low level.
Turn the adjustor Hto the right or the adjustor Ifor low level to the left.
■ Signal high level too frequently
Raise the switchpoint high level or lower the switchpoint pump off.
Turn the adjustor Eto the right or the adjustor Fto the left.
If it is not possible to make this rectification install a time relay to delay the signal low level by
2 to 20 sec.
Correct switchpoints
Check power
Danger
The terminal strip of the NRS 2-3 is live during operation. This presents the danger of
electric shock.
Cut off power supply before removing or inserting the 19" slide-in unit or undertaking any
kind of installation or maintenance work.
Note
The level switch NRS 2-3 can only be operated and checked in combination with the
level transmitter NRGT 26-1S.

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Operational Malfunctions
Fault finding list for troubleshooting
After applying mains voltage LEDs Band Cdo not light up
Fault: The mains voltage is not applied across the equipment.
Remedy: Apply mains voltage. Check installation of the 19" slide-in unit.
Fault: The internal fuse is defective.
Remedy: Remove the 19" slide-in unit and replace the internal fuse.
Incorrect measuring current between electrode terminal 2 and NRS terminal 5 or A22 defective
Fault: The level transmitter NRGT 26-1S is defective.
Remedy: Check level transmitter (see installation instructions NRGT 26-1S).
Level switch does not work properly despite correct measuring current
Fault: The level switch NRS 2-3 is defective.
Remedy: Replace level switch.
Danger
The terminal strip of the NRS 2-3 is live during operation. This presents the danger of
electric shock.
Cut off power supply before inserting or removing the 19" slide-in unit and before carrying
out any installation or maintenance work.

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Declaration of conformity
Annex
We hereby declare that the equipment NRS 2-3 conforms to the following European guidelines:
■LV guideline 73/23/EC version 93/68/EC
■ EMC guideline 89/336/EC version 93/68/EC
which are based on the following harmonised standards:
■ LV standard EN 60947-5-1: 1991 73/23/EC version 93/68/EC
■ EMC standard EN 50 081-2, EN 50 082-2
This declaration is no longer valid if modifications are made to the equipment without consultation
with us.
Bremen, 28th April 1997
GESTRA AG
Quality Assurance Representative
Walter Meyer
Head of the Design Dept.
Dipl.-Ing. Uwe Bledschun
(Academically qualified engineer)

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For your notes

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810414-02/807cm
·
1997 GESTRA AG
·
Bremen
·
Printed in Germany
Agencies all over the world:
www.gestra.de
GESTRA AG
Münchener Straße 77
28215 Bremen
Germany
Telefon [phone]
Telefax [phone]
E-Mail [email protected]
Web www.gestra.de