Flowserve NRG 16-51 User Manual

GESTRA Steam Systems

NRG 16-51
NRG 17-51
NRG 19-51

Installation Instructions 818956-02

Level Electrodes
NRG 16-51, NRG 17-51, NRG 19-51

EN

English

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Contents

Page

Application

Usage for the intended purpose ..............................................................................................................4

Function .................................................................................................................................................4

Directives and Standards

Pressure Equipment Directive (PED) 97/23/EC ........................................................................................

Functional Safety acc. to IEC 61508 ........................................................................................................

VdTÜV Bulletin “Wasserstand 100” (= Water Level 100) ..........................................................................

ATEX (Atmosphère Explosible) ................................................................................................................. 5

Technical Data

NRG 16-51, NRG 17-51, NRG 19-51 .......................................................................................................

Corrosion resistance ...............................................................................................................................7

Sizing .....................................................................................................................................................7

Name plate/ marking .............................................................................................................................. 8

Dimensions NRG 16-51, NRG 17-51 .......................................................................................................

Dimensions NRG 19-51 ........................................................................................................................10

Functional Elements

NRG 16-51, NRG 17-51, NRG 19-51 .....................................................................................................11

NRG 16-51, NRG 17-51, NRG 19-51 with four-pole connector ...............................................................

NRG 16-51F, NRG 17-51F, NRG 19-51F with aluminium terminal box ....................................................13

Key .......................................................................................................................................................14

Important Notes

Safety note ...........................................................................................................................................15

Scope of supply ....................................................................................................................................15

Installation

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NRG 16-51, NRG 17-51, NRG 19-51, step 1 ..........................................................................................16

NRG 16-51, NRG 17-51, NRG 19-51, step 2 ..........................................................................................16

NRG 16-50F, NRG 17-50F, NRG 19-50, additional information ...............................................................16

Tools .....................................................................................................................................................17

Contents – continued –

Page

Examples of Installation

NRG 16-51, NRG 17-51, NRG 19-51 ..................................................................................................... 18

Key .......................................................................................................................................................19

Electrical Connection

Connection of level electrode ................................................................................................................ 20

NRG 16-51, NRG 17-51, NRG 19-51 with four-pole connector ...............................................................20

NRG 16-51F, NRG 17-51F, NRG 19-51F with aluminium terminal box ....................................................20

Wiring diagram ..................................................................................................................................... 21

Key .......................................................................................................................................................22

Tools .....................................................................................................................................................22

Commissioning, Fault Indication and Remedy

NRG 16-51, NRG 17-51, NRG 19-51 .....................................................................................................

Decommissioning

Disposal................................................................................................................................................22

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Application

Usage for the intended purpose

The level electrodes NRG 16-51, NRG 17-51 and NRG 19-51 are used in conjunction with level switch
NRS 1-51 as high water level alarms for steam boiler plants and (pressurized) hot water installations.
A high level alarm prevents the water level from exceeding the preset max. water level (HW) and for this
purpose switches off e. g. the feedwater supply.

Function

When the level exceeds the max. water level, the level electrode enters the liquid and an alarm is
triggered in the level switch NRS 1-51. The switchpoint “High level (HW) exceeded” is dictated by the
length of the electrode rod.

The self-monitoring function ensures that an alarm will also be triggered if the electrode insulation is
contaminated or has developed a leak or if there is a malfunction in the electrical connection.

The level electrode is installed inside steam boilers, vessels or inlet lines of hot-water systems. The
protective tube mounted on site (see section Examples of Installation (pages 18, 19) ensures correct
functioning.

One level electrode NRG 1...-51 can be installed together with one GESTRA water level limiting
electrode in a single protection tube or external level pot.

If the level electrode is installed in a level pot outside the boiler, make sure that the connecting lines
are rinsed regularly. In addition, the logic unit SRL is required to monitor the purging times and the
purging sequence.

If the connecting lines for steam ≥ 40 mm and water ≥ 100 mm, the installation is considered to be
internal. In this case the rinsing processes do not have to be monitored.

Directives and Standards

Pressure Equipment Directive (PED) 97/23/EC

The level electrode NRG 1...-51 in conjunction with level switch NRS 1-51 is EC type approved accord
ing to EN 12952/EN 12953. These Directives state, among other things, the requirements made on
limiting systems and equipment for steam boiler plants and (pressurised) hot-water installations.

Functional Safety acc. to IEC 61508

The level electrode NRG 1...-51 is certified acc. to IEC 61508 only if used in combination with level
switch NRS 1-51. This standard describes the functional safety of safety-related electrical/electronic/
programmable electronic systems.

The equipment combination NRG 1...-51 + NRS 1-50 corresponds to a type B subsystem with Safety
Integrity Level (SIL) 3.

VdTÜV Bulletin “Wasserstand 100” (= Water Level 100)

The level electrodes NRG 1-51, NRG 1...-12 in conjunction with the level switch NRS 1-51 are type
approved according to the VdTÜV Bulletin “Water Level 100”.

The VdTÜV Bulletin “Wasserstand (=Water Level) 100” specifies the requirements made on water level
control and limiting equipment for boilers.

ATEX (Atmosphère Explosible)

The level electrodes NRG 1...-51, NRG 1...-12 are simple items of electrical equipment as specified
in EN 60079-11 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 separate document.
Note that the requirements of the IEC 61508 are not met if the NRG 1...-51, NRG 1...-12 + Zener
barriers + NRS 1-51 are interconnected!

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Technical Data

NRG 16-51, NRG 17-51, NRG 19-51

Service pressure

NRG 16-51: PN 40, 32 bar at 238 °C
NRG 17-51: PN 63, 46 bar at 260 °C
NRG 19-51: PN 160, 100 bar at 311 °C

Mechanical connection

Screwed ¾" to EN ISO 228-1

Materials

Sheath 1.4301 X5 CrNi18-10
Screw-in body 1.4571, X6CrNiMoTi17-12-2
Measuring electrode 1.4571 X6CrNiMoTi17-12-2
Electrode rod 1.4401 X5CrNiMo17-12-2
Electrode insulation PEEK
NRG 1...-51: Four-pole connector: polyamid (PA)
NRG 1...-51F: Terminal box 3.2161 G AlSi8Cu3

Lengths available

500 mm, 1000 mm, 1500 mm

Electrical connection

NRG 1...-51:
NRG 1...-50F: Terminal box made from aluminium, cable gland M 20

Protection

IP 65 to EN 60529

Max. admissible ambient temperature

70 °C

Weight

Approx. 1.2 kg (without extension)
(NRG 16-51, NRG 17-51, NRG 19-51)
Approx. 2.1 kg (without extension)
(NRG 16-51F, NRG 17-51F, NRG 19-51F)

Approvals

EC Prototype approval PED Pressure Equipment Directive 97/23/EC, EN 12952-11, EN 12953-09:
Requirements made on limiting equipment for boilers.

Functional Safety SIL 3 IEC 61508:
Functional safety of safety-related electrical/electronic/programmable
electronic systems

TÜV type approval VdTÜV Bulletin “Wasserstand 100” (= Water Level 100):
Requirements made on water level limiting & control equipment.

Type approval no. TÜV · SHWS · XX-423
(see name plate)

Four-pole connector, cable glands M 16

Gylon® is a registered trademark of Garlock Sealing Technologies, Palmyra NY, USA

Technical Data – continued –

Corrosion resistance

If the equipment is used for the intended purpose, its safety is not impaired by corrosion.

Sizing

The body is not designed for pulsating loads. Welds and flanges are designed to withstand dynamic
loading (bending and alternative stress). The dimensional allowances and anti-corrosive additives
reflect the latest state of the technical art.

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Technical Data – continued –

Name plate/marking

Equipment designation Safety note

Disposal note
Pressure rating, thread type,

material number, type approval number
CE marking

Fig. 1

Manufacturer

Serial number

Safety note

Equipment designation, pressure rating

Screwed connection, material number,
protection

Pressure/temperature rating

CE Marking, type approval

Disposal note

Manufacturer

Fig. 2

Serial number