Flowserve NRS 2-3 User Manual

NRS 2-3

Installation Instructions 810414-01

Level Switch Type NRS 2-3

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1

Contents

Page

Important Notes

Usage for the intended purpose ......................................................................................6

Safety Note .....................................................................................................................6

Warning ...........................................................................................................................6

Explanatory Notes

System description ..........................................................................................................7

Function .......................................................................................................................... 7

Design .............................................................................................................................8

Technical data ........................................................................................................... 8 – 9

Installation

Design “b” ......................................................................................................................10

Design “c”/“d” ................................................................................................................10

Tools ..............................................................................................................................10

Wiring

Design “b” ......................................................................................................................11

Wiring diagram for design “b” ........................................................................................11

Key to wiring diagram.................................................................................................... 11

Design “c”/“d” ................................................................................................................12

Wiring diagram for design “c”/“d”................................................................................... 12

Attention ........................................................................................................................12

Commissioning

Warning .........................................................................................................................13

Check wiring.................................................................................................................. 13

Apply mains voltage ......................................................................................................13

Adjust switchpoint “Low Level” ......................................................................................13

Adjust switchpoint “Pump
Adjust switchpoint “Pump

ON” ........................................................................................13

OFF” ......................................................................................14

Adjust switchpoint “High Level” ..................................................................................... 14

Table “Switchpoints” ......................................................................................................14

Operation

Warning .........................................................................................................................15

Correct switchpoints ......................................................................................................15

Check power .................................................................................................................15

Annex

Warning .........................................................................................................................16

Fault finding list for troubleshooting ............................................................................... 16

Declaration of conformity .............................................................................................. 17

2

Dimensions

207

7 9 10 11 12 13 14 15

NRS 2-3

OFF

ON

16654321

67.7
80

∅ 6

MAX

88

180

MIN

17

Fig. 1

169

NRS 2-3

MAX

OFF

ON

MIN

45.3 (9TE)

(TE = division units)
(1 TE = 5.08 mm)

128.5

3

Parts Drawings

7 9 10 11 12 13 14 15

NRS 2-3

D

C

C

MAX

OFF

E

F

KJ

ON

B

A

MIN

16654321

17

H

I

NRS 2-3

MAX

L

MAX 70 °C

OFF

4

ON

MAX 95 %

MIN

IP 10

Fig. 2

Key

A

LED “Low Level”

B

LED “Pump

C

LED “Pump

D

LED “High Level”

E

Adjustor for high level

F

Adjustor for pump

H

Adjustor for pump ON

I

Adjustor for low level

J

Fixing screws

K

Screw-type terminal strip

L

32way Euro card connector

ON”

OFF“

OFF

5

Important Notes

Usage for the intended purpose

Use level switch NRS 2-3 only in conjunction with GESTRA level transmitter
NRGT 26-1 as pump control.

Safety Note

The equipment must only be installed by qualified staff.
Qualified staff are those persons who – through adequate training in electrical

engineering, the use and application of safety equipment in accordance with
regulations concerning electrical safety systems, and first aid & accident
prevention – have achieved a recognised level of competence appropriate to
the installation and commissioning of this device.

Warning

The terminal strip of the NRS 2-3 is live during operation. This presents
the danger of electric shock.
Cut off power supply before inserting or removing the 19" slide-in unit and
before carrying out any installation or maintenance work.

6

Explanatory Notes

Scope of supply

NRS 2-3, design “b”

1 Level switch NRS 2-3
1 Mounting panel for installation in control cabinets
1 Installation manual

NRS 2-3, design “c”

1 Level switch NRS 2-3
2 Guide rails
1 32 pole screw-type connector
1 Installation manual

NRS 2-3, design “d”

1 Level switch NRS 2-3
1 Installation manual

System description

The level switch type NRS 2-3 is an analogue electronic control instrument (pump
control) for the capacitance level transmitter type NRGT 26-1.

In combination with this transmitter the switch can signal the following levels:
High level, low level, level control unit
and can be used as level controller for steam boilers and pressurized hot-water plants.

Function

ON/OFF

The standardized input current signal is transformed by the resistor into a level­proportional voltage and then preamplified. This voltage is fed to three voltage
comparators V1, V2, V3 and compared with adjustable reference voltages. Depending
on the comparison result the relays will be (de)energized as follows:

■

If the level voltage across V1 is higher than the reference voltage, relay 1 is
de-energized and the red LED illuminated.

■

If the level voltage across V3 is lower than the reference voltage, relay 3 is
de-energized and the red LED illuminated.

■

If the level voltage across V3 is higher than the reference voltage, relay 3 is
energized and the red LED extinguishes.

D

A

A

V2 works as switching controller, e. g. for the boiler feed pump.

■ If the level voltage across V2 is lower than the reference voltage, relay 2 will switch

on the pump. The yellow LED is illuminated.

B

The pump switches off in accordance with the adjusted hysteresis, which is adjustable
over 1 % to 50 % of the level transmitter measuring range. Once the adjusted value is
reached the relay 2 switches off the pump and the green LED is illuminated.

C

7

Explanatory Notes – continued –

Designs

Design “b”

19" slide-in unit to DIN 41494 part 5, installed on a mounting panel for installation
in control cabinets with screw-type terminals at the top and bottom.

Design “c”

19" slide-in unit with guide rails and 32 pole screw-type connector for the installation in
19" mounting panels acc. to DIN 41494 part 5.

Design “d”

19" spare slide-in unit

Technical Data

Type approval no.

GL 99249-96HH

Mains voltage

230 V ± 10%, 50/60 Hz
115 V ± 10%, 50/60 Hz (option)
24 V ± 10%, 50/60 Hz (option)

Power consumption

5 VA

Input

4 – 20 mA (coming from level transmitter)

Output

3 volt-free relay contacts
Max. contact rating with switching voltages of 24V, 115 V and 230 V AC: 4A resistive,

0.75 A inductive at cos ϕ = 0.5.
Max. contact rating with a switching voltage of 24V DC: 4A
Service life of relay: 30 x 10

Limit value

HIGH LEVEL/LOW LEVEL

6

switching cycles.

Continuously adjustable within measuring range of level transmitter

Switchpoints

PUMP ON /OFF

Continuously adjustable within 1– 50 % of the measuring range of level transmitter

Indicators and adjustors

1 red LED “
1 green LED “
4 adjustors for

HIGH LEVEL”, 1 red LED “LOW LEVEL”, 1 yellow LED “PUMP ON”,

PUMP OFF”.

HIGH LEVEL/LOW LEVEL and PUMP ON/ OFF.

Protection

IP 10 to DIN EN 60529

8

Explanatory Notes – continued –

Technical Data – continued –

Max. admissible ambient temperature

0°C to +70 °C

Case

19" slide-in unit with front panel to DIN 41494 part 5 and rear 32 way Euro card
connector to DIN 41612 installed in a mounting panel or for installation in
19" mounting panel.
Front panel, mounting panel: aluminium

Wiring
Design “b”: screw-type terminal strips at the back of the mounting panel, max.

conductor size 1.5 mm²
Design “c”: 32 pole screw-type connector at the back of the 19" mounting panel, max.
conductor size 1.5 mm²
Supply line to level transmitter: screened two-core cable, conductor size 0.5 mm²,
max. cable length 150 m

Internal fuse

Glass cartridge fine-wire fuse M 0.05 A, 5 x20, replaceable

Weight

approx. 0.8 kg

9

Installation

Design “b”

1. Drill four holes into the mounting panel of the control cabinet.

2. Put level switch onto the mounting panel and align.

3. Insert matching screws and fasten.

Design “c”/“d”

1. Install guide rails and screw-type connector into 19" mounting panel.

2. Insert 19" slide-in unit into the guide rails until it hits the stop.

3. Fasten the fixing screws .

Tools

■

Screwdriver for slotted screws, size 2mm, 5 mm, completely insulated to VDE 0680

J

10

Wiring

Design “b”

Wiring is effected via the two screw-type terminal strips. Use screened two-core cable,
conductor size 0.5 mm², max. cable length 150 m for the supply of the level
transmitter.

Wiring diagram for design “b”

G 2.5 A

2

3

4

1

5

Fig. 3 Example of fill control with second level indicator

Key to wiring diagram

1

Level transmitter, output 4 –20 mA

2

High level

3

Water level controller (fill control)

4

Low level (LED red/green)

5

Connection for another device, e. g. NRR 2-3

11

Wiring – continued –

Design “c”/“d”

Wiring is effected via the 32 pole screw-type connector.
Use screened two-core cable, conductor size 0.5 mm², max. cable length 150 m for
the supply of the level transmitter.

Wiring diagram for design “c”/ “d”

2

3

4

1

12

5

Fig. 4

Attention

■

Protect the control circuit with a 2.5 A (slow blow) fuse.

■

Connect screen only to the assigned terminal of the NRS 2-3.

■

The screen must not make any other electrical contact.

■

When switching off inductive loads, voltage spikes are produced that
may impair the operation of control and measuring systems. Inductive
loads should therefore be provided with commercial arc suppressor
RC combinations, e. g. 0.1 µF/ 100 Ω.

Commissioning

Warning

The terminal strip of the NRS 2-3 is live during operation. This presents the
danger of electric shock.
Cut off power supply before removing or inserting the 19" slide-in unit or
undertaking any kind of installation or maintenance work.

Note

The level switch NRS 2-3 can only be operated and checked in
combination with the level transmitter NRGT 26-1s.

Check wiring

1. Check whether the 19" slide-in unit has been properly installed in the mounting
panel.

2. Check whether the mains supply corresponds to the wiring carried out on the
equipment.

Apply mains voltage

1. Switch on the mains supply and verify that the NRS 2-3 is receiving power. The

B C

LED or will illuminate to verify this.

Adjust the switchpoint “Low Level”

1. Fill the tank and observe the level indicator until the water has reached the desired
level.

2. Turn the adjustor from the left stop slowly to the right just until the red LED

I A

lights up.

Adjust the switchpoint “Pump ON”

1. Raise the water level in the tank until the desired switchpoint for the feedpump is
reached.

2. Turn the adjustors and to the left stop.

3. Turn the adjustor from the left stop to the right until the yellow LED lights up.

4. Turn the adjustor to the right stop. The green LED is not illuminated.

F H

H B

F C

13

Commissioning – continued –

Adjust the switchpoint “Pump OFF”

1. Raise the water level in the tank until the desired switchpoint for the pump is
reached.

2. Turn the adjustor to the left until the green LED

3. Carry out a final adjustment during operation: Adjust such that the exact
switchpoint is achieved. Turning to the right increases the separation between the
pump on and pump off positions.

Adjust the switchpoint „High level“

1. Fill the tank until the max. admissible water level is reached.

2. Turn the adjustor from the right stop slowly to the left until the red LED
lights up.

Note

F C

E D

PUMP OFF lights up.

F

You can directly change the switchpoints over the whole measuring range
of the level transmitter by using the adjustors for LOW LEVEL, for PUMP

ON

E

and for HIGH LEVEL. To avoid confusion of the switchpoints during

I H

commissioning, we recommend that the above-mentioned sequence is
carefully followed.
The adjustor for

PUMP ON only.

F

PUMP OFF is for changing the distance to the switchpoint

Table 1 Switchpoints

Mark the adjusted switchpoints either on the water level indicator and/or enter the data
into the following table:

Switchpoint (above the lowest water level)

OW level ...................... mm

L
Pump

ON ...................... mm

OFF ...................... mm

Pump
H

IGH level ...................... mm

14

Operation

Warning

The terminal strip of the NRS 2-3 is live during operation. This presents the
danger of electric shock.
Cut off power supply before removing or inserting the 19" slide-in unit or
undertaking any kind of installation or maintenance work.

Note

The level switch NRS 2-3 can only be operated and checked in combination
with the level transmitter NRGT 26-1s.

Correct switchpoints

During operation you have to correct the switchpoints if the following
malfunctions occur:

■

Pump is switched on and off too frequently
Increase the distance between the switchpoints
adjustor to the right.

■

Signal LOW LEVEL too frequently
Raise the switchpoint
Turn the adjustor to the right or the adjustor for

■

Signal HIGH LEVEL too frequently
Raise the switchpoint
Turn the adjustor to the right or the adjustor to the left.

F

PUMP ON or lower the switchpoint LOW LEVEL.

H I

HIGH LEVEL or lower the switchpoint PUMP OFF.

E F

If it is not possible to make this rectification install a time relay to delay the signal

LOW LEVEL by 2 to 20 sec.

PUMP ON and PUMP OFF. Turn the

LOW LEVEL to the left.

Check power

1. Check the measuring current coming from the level transmitter across the
terminals 5(+) and 6(–) in the case of design “b” and A22/C24 in the case of
design “c” and “d”.
Measuring current: 4 to 20 mA

15

Annex

Warning

The terminal strip of the NRS 2-3 is live during operation. This presents the
danger of electric shock.
Cut off power supply before inserting or removing the 19" slide-in unit and
before carrying out any installation or maintenance work.

Fault finding list for troubleshooting

After applying mains voltage LEDs and do not light up

Fault: The mains voltage is not applied across the equipment.
Remedy: Apply mains voltage. Check installation of the 19" slide-in unit.

Fault: The internal fuse is defective.
Remedy: Remove the 19" slide-in unit and replace the internal fuse.

Incorrect measuring current between electrode terminal 2 and NRS terminal
5 or A22 defective

Fault: The level transmitter NRGT 26-1s is defective.
Remedy: Check level transmitter (see installation instructions NRGT 26-1s).

Level switch does not work properly despite correct measuring current

Fault: The level switch NRS 2-3 is defective.
Remedy: Replace level switch.

B C

16

Annex – continued –

Declaration of conformity

We hereby declare that the equipment NRS 2-3 conforms to the following European
guidelines:

■

LV guideline 73/23/eec version 93/68/eec

■

EMC guideline 89/336/eec version 93/68/eec

which are based on the following harmonised standards:

■

LV standard EN 60947-5-1: 1991 73/23/eec version 93/68/eec

■

EMC standard EN 50 081-2, EN 50 082-2

This declaration is no longer valid if modifications are made to the equipment without
consultation with us.

Bremen, 28th April 1997

GESTRA GmbH

Head of the Design Dept.

Uwe Bledschun

Academically qualified engineer

Quality Assurance Representative

Walter Meyer

17

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A Unit of Flowserve Corporation

810414-01/1102c · © 1997 GESTRA GmbH · Bremen · Printed in Germany