GESTRA NRS 1-8 User manual
1
NRS 1-8
Installation Instructions 818612-03
Level Switch NRS 1-8
GESTRA Steam Systems
EN
English
2
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......................................................................................................................................4
Description .............................................................................................................................................4
Function .................................................................................................................................................5
System components ...............................................................................................................................5
Design....................................................................................................................................................5
NRS 1-8................................................................................................................................................12
Attention...............................................................................................................................................12
Tools.....................................................................................................................................................12
Key.......................................................................................................................................................12
Examples of installation ........................................................................................................................13
Installation
Electrical Connection
NRS 1-8................................................................................................................................................14
Voltage table.........................................................................................................................................14
Attention...............................................................................................................................................14
Notice...................................................................................................................................................14
Tools.....................................................................................................................................................14
Wiring diagram.....................................................................................................................................15
NRS 1-8..................................................................................................................................................6
Corrosion resistance...............................................................................................................................7
Name plate/marking ............................................................................................................................... 7
Dimensions.............................................................................................................................................8
Technical Data
NRS 1-8..................................................................................................................................................9
Key.......................................................................................................................................................11
Component Parts
NRS 1-8................................................................................................................................................10
Key.......................................................................................................................................................11
Functional Elements
3
Checking electrical connection .............................................................................................................16
Applying mains voltage.........................................................................................................................16
Contents – continued –
Commissioning
Page
Water level limiter.................................................................................................................................17
Notice...................................................................................................................................................17
Operation
Fault finding list for troubleshooting................................................................................................ 17, 18
Operational Malfunctions
Danger .................................................................................................................................................18
Disposal................................................................................................................................................18
Decommissioning
Water level limiter.................................................................................................................................16
Performance Test
Declaration of Conformity .....................................................................................................................19
Annex
4
Important Notes
Danger
The terminal strips of the NRS 1-8 are live during operation.
This presents the danger of electric shock!
Cut off power supply before mounting or removing the terminal strips and the
housing cover.
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 water level limiting (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.
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 limiter). Application in steam and
pressurised hot water plants in accordance with TRD 602, sheet 1 and sheet 2 as well as EN 12952
and 12953.
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 94/9/EC 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. The suitability of the Zener barriers is certified in a separate document.
Attention
The name plate specifies the technical features of the equipment. Note that any item of
equipment without its specific name plate must neither be commissioned nor operated.
5
Explanantory 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. The self-checking is effected periodically. During the
test the cable between electrode and level switch and the self-checking circuitry (redundancy) are
checked.
The output relays are not influenced by the internal tests.
The level switch can also be tested manually by pushing the button “TEST 1” to simulate a mal-
function in the level electrode.
The toggle switch “TEST 2 / INSPECTION” is designed for testing the function of the self-checking
routine by simulating a malfunction. The contact relays are of the normally closed type and will
automatically signal alarm condition in the event of a malfunction. The level switch can signal the
following three operating conditions:
nNormal operation (correct water level in boiler)
nAlarm (level in boiler too high)
nAlarm (malfunction in level switch or level electrode)
A green LED indicates power supply. Two red LEDs signal an alarm in the event of high water level or
system malfunction.
The failure of one channel (loss of redundancy) is signalled by one red LED.
The equipment combination of electrode NRG 16-12, NRG 17-12 or 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. Remove cover to access the terminals
in the housing base. Thanks to the code plug the equipment cannot be connected inadvertently to
wrong GESTRA equipment. The equipment may be snapped onto a 35 mm supporting rail or screwed
into position on a mounting panel.
6
NRS 1-8
Technical Data
TÜV approval
TÜV · HWS · 08-417
Input
Four terminals for one level electrode
NRG 16-12, PN 40
NRG 17-12, PN 63
NRG 19-12, PN 160
Output
Two volt-free relay contacts
Max. contact rating: 250 V, 300 W, 3 A resistive with a life of 5 x 105switching cycles
or 0.35 A inductive with a life of 2 x 106switching cycles. Contact material: silver, hard-gold plated.
Delay of response
Default factory setting: 3 sec.
Up to 25 sec. after prior consultation with TÜV.
Sensitivity of response
10 µS/cm at 25 °C when used in conjunction with level electrode without measuring surface extension
and cell constant 0.3.
0.5 µS/cm at 25 °C when used in conjunction with level electrode with measuring surface extension and
cell constant 0.13 (see data sheet NRG 16-12).
Indicators and adjustors
Two LEDs for “Alarm”, one LED for “Power”, one button “TEST 1”,
one toggle switch “TEST 2 / INSPECTION”.
Mains voltage
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.
When using the ancillary unit URN 1 the equipment can also be fed with 24 V DC.
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
7
Corrosion resistance
If the equipment is used for the intended purpose, its safety is not impaired by corrosion.
Technical Data – continued –
Name plate/marking
Equipment designation
Fig. 1
Mains voltage
Sensitivity of response
Delay of response
External fuse
8
Technical Data – continued –
Dimensions
Fig. 2
106 7
32
51
Fig. 3
112
85
9
Component Parts
72 3
6
5
4
Fig. 4 Fig. 5
Fig. 6
1
NRS 1-8
1
10
Fig. 7
b
9
0
a
MAX 55°C
MAX 95%
%
IP 65
Functional Elements
NRS 1-8
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