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Summary of Contents for GESTRA NRS 1-51
- Page 1 Level Switch NRS 1-51 Original Installation & EN (USA) Operating Manual 850695-00 English...
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Page 2: Table Of Contents
Connecting the level electrode ....................... 19 Connecting the control circuit ......................19 Connecting the signal output ......................20 Wiring diagram of level switch NRS 1-51 ..................21 Example switching combinations ....................22 NRS 1-51 - USA - Installation & Operating Manual - 850695-00... - Page 3 Action against high-frequency interference ..................26 Interlock and interlock deactivation ....................26 Checking switchpoints ........................26 Taking out of service .......................... 27 Disposal .............................. 27 UL components ........................... 27 NRS 1-51 - USA - Installation & Operating Manual - 850695-00...
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Page 4: Content Of This Manual
All rights reserved. Any misuse, particularly reproduction and dissemination to third parties, is not permitted. The General Terms & Conditions of GESTRA AG apply. Scope of supply, product package NRS 1-51 1 level switch NRS 1-51 1 Installation & Operating Manual NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 5: How To Use This Manual
How to use this Manual This Installation & Operating Manual describes the correct use of the NRS 1-51 level switch. It applies to persons who integrate this equipment in control systems, install, bring into service, operate, maintain and dispose of this equipment. Anyone carrying out the above-mentioned activi- ties must have read this Installation &... -
Page 6: Types Of Warning
Warning of a dangerous situation that may possibly result in death or serious injury. CAUTION Warning of a situation that may result in minor or moderate injury. ATTENTION Warning of a situation that results in damage to property or the environment. NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 7: Specialist Terms, Abbreviations
A boiler that is operated at 145 psi (10 bar) and 356°F (180°C) may be designed to withstand a pressure of 870 psi (60 bar) and a temperature of 527°F (275°C), for example, which is therefore not necessarily its operating point. NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 8: Usage For The Intended Purpose
Usage for the intended purpose The NRS 1-51 level switch is used in conjunction with NRG 1...-51 level electrodes as a high level alarm for steam boilers and hot water installations. A high level alarm prevents the defined high water (HW) level from being exceeded and switches off the feedwater supply, for example, to achieve this. -
Page 9: Basic Safety Information
Check that the plant is not carrying live voltage before commencing work. ■ Attempts to repair the equipment will cause the plant to become unsafe. The NRS 1-51 level switch may only be repaired by the manufacturer, GESTRA AG. ■ Only replace faulty equipment with identical equipment from GESTRA AG. -
Page 10: Required Personnel Qualifications
Persons trained by the plant operator to work Refits Specialist staff with pressure and temperature. Notes on product liability The manufacturer cannot accept any liability for damages resulting from improper use of the equipment. NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 11: Function
Function The NRS 1-51 level switch is designed for different boiler water conductivities and for the con- nection of a single level electrode. When the water exceeds the high water level, the level electrode is immersed and an alarm is triggered in the level switch. -
Page 12: Technical Data
Relative humidity Max. 95%, non-condensing Site altitude Max. 6560 ft (2000 m) Other information Incorporated Type 2 action protective control Class B (C) Pollution degree 2, impulse voltage 2500 V NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 13: Rating Plate, Identification
Wiring: Use Copper Conductors Only, OPERATING CONTROL Use 60/75°C Conductors, E513189 Use No.18 16 AWG Wire Size Only, Tightening: Torque 0.79Nm or 7lb in. NRS 1-51 - USA - Installation & Operating Manual - 850695-00 Use with accessory: NRG16,17,19,111 12, 51, 51(F) -
Page 14: Factory Default Settings
There is a risk of electric shock during work on electrical systems. Switch off the voltage to the plant before you install the equipment. ■ Check that the plant is not carrying live voltage before commencing work. ■ NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 15: Dimensions Of The Nrs 1-51
Dimensions of the NRS 1-51 3.94 in (100 mm) Test Fig. 3 Upper terminal strip Lower terminal strip Fastening screws (cross recess head screw M3) Terminal box Support rail TH 35, EN 60715 NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 16: Important Notes
Fitting and maintenance work may only be performed by authorized staff who have undergone specific training. Danger The terminal strips of the NRS 1-51 level switch are live during operation! There is a risk of serious injury due to electric shock. Before working on terminal strips (installation, removal, connection of cables), always cut off power to the equipment. -
Page 17: Preparing For Installation
Use UV-resistant cable ducts for routing the connecting cable. ■ Take further measures to protect the equipment from lightning, insects and ■ animals, and salty air. You will need the following tools: Pozidriv screwdriver size PZ1 ■ NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 18: Installation
ATTENTION Incorrect installation can lead to malfunctions in the plant or the level electrode. The NRS 1-51 level switch snaps onto a TH 35, EN 60715 support rail in a control cabinet. Fig. 3 7 NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 19: Electrical Connection
If cutting the feed- water supply poses a danger to heating surfaces in the feedwater pre-heater, the heating must be switched off as well. In the event of an alarm, the NRS 1-51 level switch interlock does not take place ■ automatically. -
Page 20: Connecting The Signal Output
A safety power supply unit (SELV / PELV / CLASS2) must be used to supply ■ the NRS 1-51 level switch with 24 V DC. This must provide a level of isolation against dangerous contact voltages that at least meets the requirements for dou- ble or reinforced insulation in accordance with UL 60730-1 (protective electrical isolation). -
Page 21: Wiring Diagram Of Level Switch Nrs 1-51
Signal output 1 / 2 for external alarm 24 V DC, 100 mA (semiconductor output) Control circuit, input and output Jumper, provided by customer Level electrode NRG 1...-51 CGP Central grounding point in control cabinet NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 22: Example Switching Combinations
Fig. 5 Fig. 6 Steam boiler plants Figure 5 Combination consisting of 1x NRG 1...-51 level electrode plus NRS 1-51 level switch as a high level alarm. For further uses, please refer to the regulations in your country Figure 6 Combination consisting of 1x NRG 1...-51 level electrode plus NRS 1-51 level switch as a high... -
Page 23: Checking The Switchpoint And Function
Check level electrode installation and make Upper pressure relief Control circuit open. sure that the level in the protective tube corre- hole is flooded. sponds to the actual water level. NRS 1-51 - USA - Installation & Operating Manual - 850695-00... -
Page 24: Operation, Alarm And Test
Supply voltage: Is the level switch supplied with the voltage specified on the rating plate? Wiring: Does the wiring conform to the wiring diagram and your chosen switching combination? NRS 1-51 - USA - Installation & Operating Manual - 850695-00... - Page 25 Relay error. flashes Once the error has been rectified, the level switch reverts to normal operation. After troubleshooting, please switch the supply voltage off and on again after approx. 5 s. NRS 1-51 - USA - Installation & Operating Manual - 850695-00...
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Page 26: Important Notes
■ Suppress HF interference using hinged-shell ferrite rings. Interlock and interlock deactivation In the event of an alarm, the NRS 1-51 level switch interlock does not take place automatically. If the installation requires an interlock, this must be implemented in the downstream (control) circuit. -
Page 27: Taking Out Of Service
Release the slider holder to detach the level switch and remove it from the support rail. ■ Disposal Dispose of the level switch in accordance with statutory waste disposal regulations. UL components The NRS 1-51 level switch is registered under XACN.E513189 NRS 1-51 - USA - Installation & Operating Manual - 850695-00... - Page 28 You can find our authorized agents around the world at: www.gestra.com GESTRA AG Münchener Straße 77 28215 Bremen Germany Tel. +49 421 3503 0 +49 421 3503 393 e-mail info@de.gestra.com www.gestra.com 850695-00/08-2021cm (809140-00) · GESTRA AG · Bremen...
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