Flowserve NRG 16-50 - Manual (Page 4)

4
Application
Usage for the intended purpose
The level electrodes NRG 6-50, NRG 7-50, NRG 9-50 and NRG -50 are used in conjunction
with level switch NRS -50 as water level limiters for steam boiler plants and (pressurised) hot water
installations.
Water level limiters switch off the heating when the water level falls below the set minimum level
(low water).
Function
When the water level falls below the low level, the level electrode is exposed and a low level alarm is
triggered in the level switch NRS -50. This switchpoint “Low water level (LW)” is determined by the
length of the electrode tip.
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 8, 9) ensures correct
functioning.
One level electrode NRG ...-50 can be installed together with one GESTRA level electrode, one level
switch or transmitter for water level control and high level alarm in one single protection tube or level
pot.
If the level electrode is installed in an isolatable 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 ≥ 00mm, the installation is considered to be
internal. In this case the rinsing processes do not have to be monitored.