Flowserve NRS 1-50 For ONE Electrode - Manual (Page 13)

3
Electrical Connection
Connection of level electrode
To connect the level electrode use screened multi-core control cable with a min. conductor size
0.5 mm  , e.g. LiYCY 4 x 0.5 mm  .
Max. length 00 m with an electrical conductivity of the boiler water > 0 μS/cm at 5 °C.
Max. length 30 m with an electrical conductivity of the boiler water < 0 μS/cm at 5 °C.
Wire terminal strip in accordance with the wiring diagram.
Fig. 5.
Connect screen only to terminal 5.
Connect the safety circuit for the heating to terminals 3, 4 and 6, 7. Wenn used as water level
limiter according to TRD, EN 95 / EN 953 connect the output contacts of the two monitoring
channels by adding a wire link between the terminals 4 and 6.
Fuse the output contacts with a  A or  A (for 7 hours operation acc. to TRD 604) slow-blow fuse.
Connection of safety circuit
Installation
Mounting level switch NRS 1-50
The level switch NRS -50 is clipped onto the support rail type TH 35, EN 6075 in the control cabinet.
Fig. 6 5
For connecting the level switch with the logic unit use a control cable, e. g.  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 -50 does not interlock automatically.
If an interlocking function in the installation is required, the follow-up circuit (safety
circuit) must be equipped with an interlock. The circuitry must meet the requirements
of the EN 5056.
A signal output for the connection of further external signalling equipment is allocated to each monitor-
ing channel in the level switch, max. load 00 mA. For connecting the level switch with the logic unit
use a control cable, e. g.  x 0.5 mm  . In the event of an alarm or error message the signal outputs
(terminals 0,  and 9, 30) open instantaneously.
Connection for signal output
Mains supply
Fuse the level switch NRS -50 with an external semi-delay fuse 0.5 A.