Flowserve NRS 1-50 For TWO Electrodes User Manual download pdf (Page 13)

Electrical Connection

Connection of level electrode

To connect the level electrode(s) use screened multi-core control cable with a min. conductor size

0.5 mm

, e.g. LiYCY 4 x 0.5 mm

Max. length 100 m with an electrical conductivity of the boiler water > 10 μS/cm at 25 °C.

Max. length 30 m with an electrical conductivity of the boiler water < 10 μS/cm at 25 °C.

Wire terminal strip in accordance with the wiring diagram. Fig. 5.

Connect screens only to terminals 5 and 13.

Connect the safety circuit for the heating to terminals 23, 24 and 26, 27. Wenn used as water level

limiter according to TRD, EN 12952 / EN 12953 connect the output contacts of the two monitoring

channels by adding a wire link between the terminals 24 and 26.

Provide the output contacts with a 2 A or 1 A (for 72 hours operation acc. to TRD 604) slow-blow fuse.

Connection of safety circuit

Installation

Mounting level switch NRS 1-50

The level switch NRS 1-50 is clipped onto the support rail

7 type TH 35, EN 60715 in the control

cabinet.

Fig. 6

For connecting the level switch with the logic unit use a control cable, e. g. 2 x 0.5 mm

The control voltage must not exceed 36 V DC.

Connection of logic unit (standby input)

Note

n In the event of an alarm the level switch NRS 1-50 does not interlock automatically.

If a lock function is required by the installation it must be provided in the follow-up

circuitry (safety circuit). The circuitry must meet the requirements of the EN 50156.

A signal output for the connection of further external signalling equipment is allocated to each

monitoring channel in the level switch, max. load 100 mA. For connecting the level switch with the

logic unit use a control cable, 2 x 0.5 mm

. In the event of an alarm or error message the signal

outputs (terminals 20, 21 and 29, 30) open instantaneously.

Connection for signal output

Mains supply

Provide the level switch NRS 1-50 with an external semi-delay fuse 0.5 A.

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 27 28

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Flowserve NRS 1-50 For TWO Electrodes User Manual Page 13