GESTRA
GESTRA Steam Systems
NRS 1-8
Installation Instructions 818612-00
Level Switch NRS 1-8
1
2
Contents
Page
Important Notes
Usage for the intended purpose ..............................................................................................................4
Safety note .............................................................................................................................................4
Danger ...................................................................................................................................................4
ATEX (Atmosphère Explosible) .................................................................................................................4
Explanatory Notes
Scope of supply ......................................................................................................................................4
Description .............................................................................................................................................4
Function .................................................................................................................................................5
System components ...............................................................................................................................5
Design ....................................................................................................................................................5
Technical Data
NRS 1-8
..................................................................................................................................................6
Corrosion resistance ...............................................................................................................................7
Name plate / marking .............................................................................................................................7
Dimensions .............................................................................................................................................8
Design
NRS 1-8..................................................................................................................................................9
Key ....................................................................................................................................................... 11
Functional Elements
NRS 1-8................................................................................................................................................10
Key ....................................................................................................................................................... 11
Installation
NRS 1-8................................................................................................................................................12
Attention ............................................................................................................................................... 12
Tools .....................................................................................................................................................12
Key ...................................................................................................................................................... 12
Examples of installation ........................................................................................................................13
Wiring
NRS 1-8
................................................................................................................................................14
Voltage table .........................................................................................................................................14
Attention ............................................................................................................................................... 14
Note .....................................................................................................................................................14
Tools .....................................................................................................................................................14
Wiring diagram .....................................................................................................................................15
Contents – continued –
Page
Commissioning
Checking wiring ....................................................................................................................................16
Apply mains voltage..............................................................................................................................16
Performance test
High-level limiter ..................................................................................................................................16
Operation
Water-level alarm .................................................................................................................................17
Note .....................................................................................................................................................17
Operational Malfunctions
Fault-finding list for troubleshooting malfunctions .................................................................................17
Decommissioning
Danger .................................................................................................................................................18
Disposal................................................................................................................................................18
Annex
Declaration of Conformity CE ................................................................................................................19
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4
Important Notes
Usage for the intended purpose
Use level switch NRS 1-8 only in conjunction with level electrodes NRG 16-12, NRG 17-12, NRG 19-12
for level control (high level alarm).
Safety note
The equipment must only be installed and commissioned by qualified 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 strip of the NRS 1-8 is live during operation. This presents the danger
of electric shock!
Cut off power supply before attaching or detaching the housing lid and the terminal
strips of the equipment.
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 atmosphers if it is provided with approved Zener barriers.
Applicable in Ex zones 1, 2 (1999/92/EC). The equipment does not bear a CE marking. The suitability of
the Zener barriers is certified in a separate document.
Explanatory Notes
Scope of supply
NRS 1-8
1 Level switch NRS 1-8
1 Installation manual
Description
Self-monitoring high-level alarm with periodic self-checking routine, designed for use in conjunction
with level electrodes NRG 16-12, PN 40, NRG 17-12, PN 63, NRG 19-12, PN 160. The equipment
combination detects the max. water level (high level alarm).
Application in steam and (pressurized) hot water boilers in accordance with TRD 602 and TRD 604
sheet 1 and sheet 2 as well as EN 12952 and EN 12953.
Explanatory Notes – continued –
Function
The level switch NRS 1-8 is a two-channel unit provided with an automatic self-checking circuitry in
accordance with DIN VDE 0116 prEN 50156 (directives for protection circuits). The self-checking is
effected periodically. The test includes the checking of the cable between electrode and level switch and
of the self-checking circuitry (redundancy). The output relays are not influenced by the internal tests.
In addition to this self-checking routine, the level switch can also be tested manually by pushing the
button “Test 1”, simulating a defect in the electrode. The test switch “Test 2/Inspection” is provided for
checking the function of the checking circuitry.
As the circuit of the relay contacts of the level switch is normally closed, alarm will also be signalled in
the event of a mains failure.
The level switch can signal the following three operating conditions:
n Normal operation (correct level)
n Alarm (high level)
n Alarm (malfunction in level switch or electrode)
The green LED indicates power supply. The high level or malfunction alarms are indicated by two red
LEDs. The failure of one channel (loss of redundancy) is signalled by the illumination of a single red LED.
The combination of electrode NRG 16-12, NRG 17-12, NRG 19-12 and level switch NRS 1-8 provides
fail-safe protection against a first fault, i. e. the system will still continue to provide the safety function
even after the occurrence of a first fault.
System components
NRG 16-12
Level electrode NRG 16-12, PN 40
NRG 17-12
Level electrode NRG 17-12, PN 63
NRG 19-12
Level electrode NRG 19-12, PN 160
Design
NRS 1-8
Plug-in unit in plastic case for installation in control cabinets. The terminals in the case are accessible
after loosening two screws and unplugging the unit from its base.
To avoid confusion with other plug-in units of the GESTRA range, inserts are fitted in the bases so that
only the correct unit may be plugged into each base.
The plug-in unit may be snapped onto a 35 mm supporting rail or screwed into position on a mounting
panel.
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6
Technical Data
NRS 1-8
Type approval no.
09 - 91 - 0112
Input
Four terminals for the connection of one level electrode
NRG 16-12, PN 40
NRG 17-12, PN 63
NRG 19-12, PN 160
Output
Two volt-free relay contacts (mounted in series in the case of design “b").
Max. contact rating: 250 V, 300 W, 3 A resistive with a life of 5 x 10
inductive with a life of 2 x 10
6
switching cycles. Contact material silver, hard-gold plated.
Delay of response
Default factory setting: 3 s
(Up to 25 s possible after prior consultation with TÜV)
Sensitivity
10 µS/cm at 25 °C when used in conjunction with level electrode without measuring surface
extension (cell constant C = 0.3).
0.5 μS/cm at 25 °C when used in conjunction with level electrode with measuring surface
extension (cell constant C = 0.13) – see data sheet “NRG 16-12”.
Indicators and adjustors
2 LEDs “Alarm”, 1 LED “Power”, 1 button “TEST 1”,
1 switch “TEST 2 / INSPECTION”.
Mains supply
230 V +/- 10 %, 50/60 Hz (please state voltage when ordering).
Special voltage: 115 V +/- 10 %, 50/60 Hz or 24 V +/- 10 %, 50/60 Hz.
The ancillary unit URN 1 can be used for 24 V d. c. supply.
Power consumption
5 VA
Protection
NRS 1-8 IP 40 to EN 60529
Admissible ambient temperature
0 °C to 55 °C
Case materials
Base: Noryl SE 1-GFN 2 UL 94 VO, black
Cover: R-ABS UL 94 VO, stone grey
Weight
Approx. 0.6 kg
5
switching cycles of 0.35 A
Technical Data – continued –
Corrosion resistance
If the equipment is used for its intended purpose, its safety is not impaired by corrosion.
Name plate / marking
Equipment designation
Fig. 1
Mains voltage
Delay of response
Sensitivity
External fuse
7
8
Technical Data – continued –
Dimensions
85
112
Fig. 2
32
51
106
7
Fig. 3
Design NRS 1-8
Fig. 4
E
F
G
A
B C
D
Fig. 5
Fig. 6
A
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10
Functional Elements
1
2
3
4
Fig. 7
Key
A Cover screws
B Base
C Cover
D Mounting clip
E Cable entry (flexible)
F Cable entry (housing)
G Hole d = 4.3 mm
1 Button “TEST 2 / INSPECTION” for internal self-checking
2 Red LED “High level alarm”
3 Button “TEST 1” for simulating a high level alarm
4 Green LED “Power”, indicating power supply
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Installation
NRS 1-8
On supporting rail (with mounting clip)
1. Clip level switch onto supporting rail.
2. Loosen cover screws
3. Select cable entry
On mounting panel
1. Loosen cover screws
2. Unscrew mounting clip
3. Drill the hole
4. Fasten base with two screws M4 onto mounting panel.
Attention
n To provide sufficient ventilation, ensure a minimum spacing of 20 mm between
Tools
n Screwdriver (5.5 / 100)
Key
A and unplug cover C from its base B.
E / F and remove corresponding seal.
A and unplug cover C from its base B.
D.
G marked in the base to ∅ 4.3 mm.
adjacent units.
A Cover screws
B Base
C Cover
D Mounting clip
E Cable entry (flexible)
F Cable entry (housing)
G Hole d = 4.3 mm
H Supporting rail 35 x 15 mm to DIN EN 50022
Installation – continued –
Examples of installation
C
A
E
D
F
F
B
H
Fig. 8
Fig. 9
G
G
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Wiring
NRS 1-8
Cable required for wiring to the electrode: four-core screened cable, e. g. I-Y(St)Y 2 x 2 x 0.8 or
LIYCY 4 x 0.5².
Max. cable length 100 m with a conductivity from 10 μS/cm.
Max. cable length 30 m with a conductivity from 0.5 μS/cm.
Max. cable length 15 m with a conductivity from 0.5 μS/cm when used in conjunction with inverter
URN 1 (24 V d. c.)
Voltage table
Use this voltage table as reference when checking the level electrode for malfunction or submersion.
Take the wiring diagram (see Fig. 10, Fig. 11) into account.
U
1-2
10 µS/cm
2 V
eff
C=0.3 cm
-1
U
1-2
0.5 µS/cm
10 V
eff
C=0.13 cm
-1
Attention
n
To protect the switching contacts provide the circuit with a 2.5 A slow-blow fuse or
according to TRD regulations (1.0 A for 72 hrs operation).
n
The screen must not make any other electrical contact.
Note
n
The self-checking routine of the amplifier NRS 1-8 reduces U
down to 0 volt.
n
Connect screen only to terminal 8 of the temperature switch.
n
The sensitivity is indicated on the name plate.
n
The rated voltage is indicated on the name plate.
n
When switching off inductive loads, voltage spikes are produced that may impair the
every 40 sec.
1-2
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.
Tools
n
Screwdriver for slotted screws, size 2.5, completely insulated according to VDE 0680-1.
Wiring – continued –
Wiring diagram
Fig. 10
Fig. 11
This wiring diagram is only applicable for France!
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16
Commissioning
Checking wiring
Check that the NRS 1-8 and the associated level electrode are wired in accordance with the wiring
diagram, Fig. 10, Fig. 11.
Apply mains voltage
Apply mains voltage to level switch NRS 1-8.
Performance test
High-level limiter
1. Check length of electrode rod (see installation manual of the level electrode).
2. When switching on the mains voltage the green LED
3. Completely open valves of water-level gauge glass on steam boiler.
4. Fill boiler with feedwater (2 cm above low level).
5. Fill up with feedwater until the max. water level (high level) is exceeded.The two red LEDs of the
level switch
If the automatic self-testing routing is activitated at this point in time an alarm will only be raised
after twice the response delay has elapsed.
6. You can simulate a high level alarm by pressing the button “TEST I” 3, with the electrode tip
submerged. Press and hold down the button until the response delay has elapsed. Both red LEDs
2 must then light up.
7. You can also test the self-checking circuitry of the level switch. With the electrode tip submerged,
operate test switch “TEST II/INSPECTION”
the two red LEDs
during this test and the level must
After the test return switch
must extinguish.
2 must light up after the response delay.
1 in the direction of the arrow. After max. two minutes
2 should signal high-level alarm. The button “TEST I” 3 must not be operated
not fall below the low level mark.
1 to its original position. After the response delay the two red LEDs 2
4 should be permanently illuminated, Fig. 7.
Operation
Water-level alarm
Application in steam and (pressurized) hot water boilers in accordance with TRD 401, TRD 602, TRD 604,
EN 12952, EN 12953 or in accordance with national regulations.
Note
n
For troubleshooting consult section “Operational Malfunctions” on page 17.
Operational Malfunctions
Fault-finding list for troubleshooting malfunctions
Electrode exposed – high-level alarm
Fault: The level switch indicates a high-level alarm before the level in the boiler has reached
the high level mark.
Remedy: Check length of the high-level electrode tip. Check correct wiring of level switch and
electrode in accordance with wiring diagram, Fig. 10, Fig. 11.
Fault: After lowering the water level below the high-level mark, the two red LEDs 2 are not
extinguished or only after quite a considerable period.
Remedy: Check whether a vent hole has been provided in the protection tube.
If the electrode is fitted in a measuring pot outside the boiler, check position of isolating
valves.
Fault: One or both red LEDs 2 light(s) up without the level having reached the high-level mark.
Remedy: This means electronic failure within the level switch, i. e. failure of one or two of the
channels. Replace level switch.
High-level reached – no function
Fault: The water level exceeds the high-level mark but neither of the two red LEDs 2 lights up.
Remedy: Check whether a vent hole has been provided in the protection tube. If the electrode is
fitted in a measuring pot outside the boiler, check position of isolating valves. Measure the
conductivity of the boiler water and compare the value obtained with the specification on
the name plate.
Fault: The testing with the switch "TEST II / INSPECTION" 1 was not successful, i. e. only one
red LED 2 or none of the two lighted up at the latest two minutes after the start of the test.
Remedy: Replace level switch.
If faults occur that are not listed above, please contact our Technical Services or agency in your country.
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18
Decommissioning
Danger
The terminal strip of the NRS 1-8 is live during operation. This presents the danger
of electric shock!
Cut off power supply before attaching or detaching the housing lid and the terminal
strips of the equipment.
Disposal
Remove the level switch and separate the waste materials in accordance with the material
specification.
Electronic components (boards) must be disposed of separately.
For the disposal of the level switch observe the pertinent legal regulations concerning waste disposal.
Annex
Declaration of Conformity
We hereby declare that the equipment NRS 1-8 conforms to the following European guidelines:
n LV guideline 73/23/eec version 93/68/eec
n EMC guideline 89/336/eec version 93/68/eec
n LV standard EN 50178
n EMC standard EN 50081-2, EN 50082-2
This declaration is no longer valid if modifications are made to the equipment without consultation
with us.
Dipl.-Ing. Uwe Bledschun
(Academically qualified engineer)
Head of the Design Dept.
Bremen, 19
GESTRA AG
th March 2004
Dipl.-Ing. Lars Bohl
(Academically qualified engineer)
Quality Assurance Manager
19
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www.gestra.de
GESTRA
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Tel. 00 34 91 / 5 15 20 32
Fax 00 34 91 / 4 13 67 47; 5 15 20 36
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Tel. 00 44 14 44 / 31 44 00
Fax 00 44 14 44 / 31 45 57
E-mail: gestraukinfo@flowserve.com
Italia
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Flow Control Division
Via Prealpi, 30
l-20032 Cormano (MI)
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Fax 00 39 02 / 66 32 55 60
E-mail: infoitaly@flowserve.com
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Ul. Schuberta 104
PL - 80-172 Gdansk
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Fax 00 48 58 / 3 06 33 00
E-mail: gestra@gestra.pl
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Porto 4100-082
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Tel.: 00 15 02 / 4 95 01 54, 4 95 17 88
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GESTRA AG
P. O. Box 10 54 60, D-28054 Bremen
Münchener Str. 77, D-28215 Bremen
Telephone +49 (0) 421 35 03 - 0
Fax +49 (0) 421 35 03 - 393
E-Mail gestra.ag@flowserve.com
Internet www.gestra.de
818612-00/106cm · © 2005 GESTRA AG · Bremen · Printed in Germany
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