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NRG 1x-60 - Installation & Operating Manual -
819681-00
Function
When the water drops below the minimum level, the level electrode is no longer immersed, and the URS
60 / URS 61 safety control unit triggers an alarm. This “Low Water (LW)” switchpoint is determined by the
length of the electrode extension.
The level electrode monitors itself using the principle of conductive measurement. This means that a leak-
ing or contaminated electrode insulator and/or a fault in the electrical connection also trigger an alarm.
The level electrode is installed inside pressurised steam systems, tanks or feed lines in pressurised
hot-water plants. A protective tube provided on site keeps it functioning reliably (see page 31 “Installa-
tion examples”).
An NRG 1x-60 level electrode can be installed in a protective tube or level pot together with an NRG 1x-61
level electrode or continuous GESTRA NRG 26-60 level electrode.
If a level electrode is installed in a lockable level pot outside the boiler, the connecting pipes must be
flushed regularly. An SRL 6-60 monitoring unit is additionally required to monitor the flushing times and
flushing process.
If the steam pipe is ≥ 40 mm and the water pipe is ≥ 100mm, installation is regarded as internal. In this
case, upstream monitoring of flushing processes is not required.
In total, two NRG 1x-60 level electrodes can be operated in conjunction with a URS 60 / URS 61 safety
control unit as a water level limiter system.
An automatic self-test cyclically monitors the safety and function of the level electrode and measured
value recorder.
The data are transferred to the URS 60 / URS 61 safety control unit in the form of a Black Channel data
telegram using the CANopen protocol via a CAN bus to ISO 11898, and saved there.
These data telegrams contain the following information:
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Alarm indications from the level electrode if water drops below the minimum level
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Fault indications in the event of faults in electronic or mechanical parts
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Excessive temperature in the level electrode terminal box
Behaviour in the event of an alarm
The Low Water alarm state is indicated by the NRG 1x-60 level electrode and transmitted to the URS 60/
URS 61 safety control unit via CAN bus. Once the time delay has elapsed, the alarm signal triggers the
safety shutoff in the safety control unit. The safety control unit does not lock automatically during this
process.
The safety circuit is interrupted without a delay if the following malfunctions occur:
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Sensor malfunction (open circuit, short circuit, faulty component, excessive temperature)
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Communication failure