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NRG 16-51, NRG 17-51, NRG 19-51 - USA - Installation & Operating Manual -
850692-00
When the water exceeds the high water level, the level electrode is immersed and an alarm is
triggered in the NRS 1-51 level switch. This “High water (HW) exceeded” switchpoint is deter-
mined by the length of the electrode extension.
The level electrode uses the conductivity of the water to measure the water level, and is
self-monitoring, i.e. an alarm is also triggered if the electrode insulator is leaking or contaminated
and/or there is a fault in the electrical connection.
Please note that a suitable protective tube needs to be provided on site during installation to
ensure safe operation. One NRG 1...-51 level electrode can be installed in a single protective tube
or level pot together with a GESTRA level electrode for water level limitation.
If the level electrode is installed in a level pot outside the boiler, the connection pipes must be
flushed regularly. The manufacturer recommends connection pipes of ≥ 1.57 in (40 mm) for
steam and ≥ 3.94 in (100 mm) for water. If smaller connection pipes are used, these must have
a minimum NPS of 1 inch. The level pot must have a suitable flushing device at its lowest point.
This device flushes the connection pipes to the boiler and enables the function of the water level
limiter to be tested. No shut-off valves of any type shall be placed in the piping between the boiler
and the low water cutoff.
Safety information
The equipment is part of a protective control according to UL 60730-1 and may only be installed,
electrically connected and brought into service by qualified and competent staff.
Fitting and maintenance work may only be performed by authorized staff who have undergone
specific training.
Attention
The rating plate indicates the technical features of the equipment. Do not bring into
service or operate any equipment that does not bear its own specific rating plate.
Danger
Please note that a suitable protective tube needs to be provided on site for an elec-
trode installed internally, to ensure safe operation. Please exercise caution when
flushing the system, as outflowing boiler water or flash steam can lead to scalding.
Please wear suitable protective clothing and do not touch any hot surfaces.
Function
