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NRG 16-51, NRG 17-51, NRG 19-51 - USA - Installation & Operating Manual -
850692-00
Installation
Installing the NRG 16-51, NRG 17-51, NRG 19-51, step 2
■
Make sure that the internal and external threads are in perfect condition.
■
Do not apply more than three windings of PTFE insulating tape around the electrode thread.
WARNING
Do not use too much tape. Do not use fitting lubricants or pastes.
■
Fit the electrode and tighten first with your hand and then with a size 41 open-ended wrench. Do
not use a pipe wrench.
■
Recommendations for tightening torques cannot be given due to the conical/parallel type of
connection.
■
Avoid tightening excessively; part of the electrode thread should always remain visible.
The electrode body does not “sit” on the flange, i.e. the underside of the hexagon is not in
contact with the flange (also see
Fig. 14
). If it is in contact, the internal thread is outside
tolerance. In this case, the flange must be replaced.
After the electrode has been installed with PTFE sealing tape, you must ensure there is adequate
electrical contact between the electrode and the boiler wall.
To do this, after installation measure the resistance between the electrode body and the boiler with
a multimeter.
The reading must be < 10 ohms.
If the reading is > 10 ohms, connect the electrode to the boiler wall using a band grounding clamp.
(The band grounding clamp is available as an optional accessory)
Next, measure the resistance again.
The value must be < 10 ohms and entered as followed:
Measured resistance: __________________________ ohms
Fig. 14
Boiler wall
Visible thread
