19
NRG 16-51, NRG 17-51, NRG 19-51 - USA - Installation & Operating Manual -
850692-00
You will need the following tools:
Note
■
One NRG 1...-51 level electrode can be installed in a single protective tube or
level pot (inside diameter 3.94 in [100 mm]) together with a GESTRA level elec-
trode, a level switch or transmitter for water level control and limitation.
Fig. 18
.
If a NRG 1...-50 level electrode is used (for water level limitation) and installed
inside the vessel, it must be at a minimum distance of 1.57 in (40 mm) from the
upper pressure relief hole.
■
Check the boiler standpipe and flange during the preliminary boiler inspection.
■
Installation examples can be found on pages 25 and 26.
■
The electrode must not be at an incline of more than 45°, and the length of the
electrode rod is limited to 39.37 in (1000 mm).
■
For outdoor installations, please use the NRG 1...-51F level electrode. Type F
level electrodes have an aluminum terminal box.
Installation
DANGER
Danger to life! Escaped hot steam can cause scalding.
Hot steam or hot water can escape suddenly if the level electrode is unscrewed under
pressure.
■
Reduce the boiler pressure to 0 psi (0 bar) and check the pressure before unscrewing
the level electrode.
■
Only remove the level electrode at 0 psi (0 bar) boiler pressure.
WARNING
The hot level electrode can cause severe burns.
The level electrode gets very hot during operation.
■
Always let the level electrode cool down before performing installation and maintenance
work.
■
Only remove level electrodes that have cooled down.
ATTENTION
Incorrect installation can lead to malfunctions in the plant or the level electrode.
■
Take care not to bend the measuring electrode during installation!
■
Do not lag the terminal head
A
or cover tube
B
(see pages 14 and 16) when
thermally insulating the boiler!
■
Do not coat the electrode thread with conductive paste or grease!
■
Make sure there is a creepage path of at least 0.55 in (14 mm) between the electrode
and ground (flange, tank wall).
Figs. 17 - 19
■
If the electrode is installed inside the vessel, it must be at least 1.57 in (40 mm) away
from the pressure relief hole in the protective tube.
