GESTRA
GESTRA Steam Systems |
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NRS 1-7 |
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Installation Instructions 818546-00 |
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Level Switch NRS 1-7 |
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1
Contents |
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Page |
Important Notes |
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Usage for the intended purpose |
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Safety note ............................................................................................................................................ |
4 |
Danger ................................................................................................................................................... |
4 |
ATEX (Atmosphère Explosible) ............................................................................................................... |
4 |
Explanatory Notes |
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Scope of supply ..................................................................................................................................... |
4 |
Description ............................................................................................................................................ |
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Function ................................................................................................................................................. |
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System components .............................................................................................................................. |
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Design ................................................................................................................................................... |
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Technical Data |
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NRS 1-7 ................................................................................................................................................. |
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Corrosion resistance .............................................................................................................................. |
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Name plate / marking ............................................................................................................................ |
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Dimensions ............................................................................................................................................ |
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Design |
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NRS 1-7 ................................................................................................................................................. |
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Key ...................................................................................................................................................... |
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Functional Elements |
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NRS 1-7 ............................................................................................................................................... |
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Key ...................................................................................................................................................... |
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Installation |
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NRS 1-7 ............................................................................................................................................... |
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Attention .............................................................................................................................................. |
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Tools .................................................................................................................................................... |
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Key ...................................................................................................................................................... |
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Examples of installation ....................................................................................................................... |
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Wiring |
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NRS 1-7 ............................................................................................................................................... |
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Voltage table ........................................................................................................................................ |
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Attention .............................................................................................................................................. |
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Note ..................................................................................................................................................... |
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Tools .................................................................................................................................................... |
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Wiring diagram .................................................................................................................................... |
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Contents – continued – |
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Commissioning |
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Check wiring ........................................................................................................................................ |
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Apply mains voltage ............................................................................................................................ |
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Performance test |
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Low-water level limiter ........................................................................................................................ |
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Operation |
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Low-water level limiter ........................................................................................................................ |
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Note ..................................................................................................................................................... |
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Operational Malfunctions |
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Fault-finding list for troubleshooting .............................................................................................. |
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Decommissioning |
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Danger ................................................................................................................................................. |
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Disposal ............................................................................................................................................... |
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Annex |
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Declaration of conformity .................................................................................................................... |
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3
Important Notes
Usage for the intended purpose
Use level switch NRS 1-7 only in conjunction with level electrodes NRG 16-11, NRG 17-11, NRG 19-11, NRG 111-11, NRG 16-11 S or NRG 16-38S for low-level limiting (low 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 1-7 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 atmospheres if it is provided with approved Zener barriers.
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.
Explanatory Notes
Scope of supply
NRS 1-7
1Level switch NRS 1-7
1Installation manual
Description
Self-monitoring low-level alarm with periodic self-checking routine, designed for use in conjunction with level electrodes NRG 16-11, PN 40, NRG 16-11S, PN 40, NRG 17-11, PN 63, NRG 19-11,
PN 160 and NRG 111-11, PN 320. The equipment combination detects the min. water level (low 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.
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Explanatory Notes – continued –
Function
The level switch NRS 1-7 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:
■Normal operation (correct level)
■Alarm (low level)
■Alarm (malfunction in level switch or electrode)
The green LED indicates power supply. The low level or malfunction alarm is 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 16-11, NRG 16-11S, NRG 17-11, NRG 19-11, NRG 111-11 and level switch NRS 1-7 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 16-11
Level electrode NRG 16-11, PN 40
NRG 16-11S
Level electrode NRG 16-11S, PN 40, for marine applications
NRG 17-11
Level electrode NRG 17-11, PN 63
NRG 19-11
Level electrode NRG 19-11, PN 160
NRG 111-11
Level electrode NRG 111-11, PN 320
Design
NRS 1-7
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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Technical Data
NRS 1-7
Type approval no.
TÜV · WB · 01-354
EG 01202931-B-01-0077
EG 01202931-B-01-0075
Input
Four terminals for the connection of one level electrode
NRG 16-11, PN 40
NRG 16-11S, PN 40
NRG 17-11, PN 63
NRG 19-11, PN 160
NRG 111-11, PN 320
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 105 switching cycles of 0.35 A inductive with a life of 2 x 106 switching cycles. Contact material silver, hard-gold plated.
Delay of response
Default factory setting: 3 s
Factory setting for marine applications: 15 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 sheets “NRG 16-11”, “NRG 111-11”.
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 1-7 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
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