GESTRA NRS 1-2 User manual
1
NRS 12
Installation Instructions 81878003
Level Switch
NRS 12
GESTRA Steam Systems
EN
English
2
Contents
Usage for the intended purpose ..............................................................................................................4
Safety note .............................................................................................................................................4
Danger ...................................................................................................................................................4
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility) .......................................................4
ATEX (Atmosphère Explosible).................................................................................................................4
Note .......................................................................................................................................................4
Note on the Declaration of Conformity / Declaration by the Manufacturer ..........................................4
Important Notes
Page
Explanatory Notes
Scope of supply......................................................................................................................................5
Description .............................................................................................................................................5
Function .................................................................................................................................................5
Components ...........................................................................................................................................5
Design....................................................................................................................................................5
NRS 12................................................................................................................................................12
Attention...............................................................................................................................................12
Tools.....................................................................................................................................................12
Key.......................................................................................................................................................12
Examples of installation ........................................................................................................................13
Installation
Electrical Connection
NRS 12................................................................................................................................................14
Note .....................................................................................................................................................14
Tools.....................................................................................................................................................14
Wiring diagram.....................................................................................................................................15
NRS 12 .................................................................................................................................................6
Name plate / marking .............................................................................................................................7
Dimensions ............................................................................................................................................8
Technical Data
NRS 12..................................................................................................................................................9
Key.......................................................................................................................................................11
Design
NRS 12................................................................................................................................................10
Key.......................................................................................................................................................11
Functional Elements
3
Checking electrical connection .............................................................................................................16
Applying mains voltage ........................................................................................................................16
Contents – continued –
Commissioning
Page
Faultfinding list for troubleshooting ............................................................................................... 17, 18
Operational Malfunctions
Danger .................................................................................................................................................18
Disposal ...............................................................................................................................................18
Decommissioning
Limit switch MIN / MAX ........................................................................................................................16
Note .....................................................................................................................................................16
Performance Test
4
Important Notes
Danger
The terminal strips of the NRS 12 are 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.
Usage for the intended purpose
Use level switch NRS 12 only in conjunction with GESTRA level electrodes NRG 164, NRG 1...52,
ER 50 and ER 56.
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.
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility)
The equipment meets the requirements of the Low Voltage Directive 2006/95/EC and the EMC Directive
2004/108/EC.
ATEX (Atmosphere Explosible)
According to the European Directive 94/9/EC the equipment must not be used in potentially explosive
areas.
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 Declaration
of Conformity or our Declaration of Manufacturer.
The current Declaration of Conformity / Declaration of Manufacturer are available in the Internet under
www.gestra.de/documents or can be requested from us.
Note
The level electrodes NRG 164, NRG 1...52, ER 50 and ER 56 are simple items of
electrical equipment as defined in EN 6007911 section 5.7. 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 sepa
rate document.
5
Scope of supply
NRS 12
1 Level switch NRS 12
1 Installation manual
Explanatory Notes
Description
Level switch for indicating one high and one low liquid level (MIN alarm, MAX alarm), designed for
use with GESTRA level electrodes NRG 164, NRG 1...52, ER 50 and ER 56. Application in steam and
(pressurised) hot water plants according to TRD 602 and TRD 604, sheet 1 and sheet 2.
Function
The level switch NRS 12 has one channel and is designed for signalling one MAX and one MIN alarm.
The level switch has a manual test function. The button “TEST LW” can simulate a malfunction in the
level electrode. As a precaution in case of a power failure the normally closed contacts will trigger an
alarm in the event of power failure. The level switch features the following four operating modes:
nNormal operation (no running dry, no high water)
nMIN alarm (running dry)
nMAX alarm (high water)
nAlarm (malfunction in level switch or level electrode)
Two red LEDs indicate low water (LW), high water (HW) or system error alarm.
Components
NRG 164
Level electrode NRG 164, PN 40
ER 50
Level electrode ER 50, NRG 1052, PN 6
ER 56
Level electrode ER 56, NRG 1652, PN 40
Design
NRS 12
Plugin 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 plugin units of the GESTRA range, inserts are fitted in the bases so
that only the correct unit may be plugged into each base.
The plugin unit may be snapped onto a 35 mm supporting rail or screwed into position on a
mounting panel.
6
NRS 12
Technical Data
Approval no.
TÜV · WR/WB · 08302
Note:
TÜV · WR/… for NRS 11, 12, 15,
TÜV…/WB… for NRS 13;
The type approval allows the combination of a water level controller and a water level limiter in
conjunction with the associated level electrodes.
Input
Three connections for two electrode rods and earth
Output
Two voltfree relay contacts,
contact rating 250 V, 500 W, 3 A resistive with a service life of 4 x 105switching cycles or
0.35 A inductive with 2 x 106switching cycles.
Contact material: silver, hardgold plated
Sensitivity of response (electrical conductivity of water at 25 °C)
> 0.5 ... < 1000 μS/cm or > 10 ... < 10000 μS/cm
Electrode voltage
11 V AC, free of direct voltage
Indicators and adjustors
1 LED for MAX alarm, 1 LED for MIN alarm, 1 button for simulating a MIN alarm
Supply voltage
24 V, 110 V, 120 V, 220 V, 240 V, 50 to 100 Hz (please indicate voltage when ordering).
When using the ancillary unit URN 1 the equipment can also be supplied with 24 V DC.
Power consumption
Approx. 3.5 VA
Protection
IP 40
Admissible ambient temperature
0 °C to 50 °C
Housing material
Base: Noryl SE 1GFN 2 UL 94 VO, black
Cover: RABS UL 94 VO, light grey
Weight
Approx. 0.8 kg
7
Technical Data – continued –
Name plate / marking
Equipment designation
Fig. 1
Supply voltage
Sensitivity of response
NRS 1-2 b
GESTRA AG Bremen
230 V 50 Hz 3,5 VA
Mat.Nr.: 056390
0,5µS/cm IP 40
Betriebsanleitung beachten
See installation instructions
Voir instructions de montage
8
Technical Data – continued –
Dimensions
Fig. 2
106 7
32
51
Fig. 3
112
85
9
Design
NRS 12
G
Fig. 6
GB C
F
E
D
Fig. 4 Fig. 5
NRS 1-2
MADE BY GESTRA
Test NW
MIN / NW
MAX / HW
A
A
10
Functional Elements
NRS 12
NRS 1-2
MADE BY GESTRA
Test NW
MIN / NW
MAX / HW
Fig. 7
4
1
3
MAX 55°C
MAX 95%
%
IP 65
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