Navien NCB300-28K, Installation & Operation Manual

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Connecting Electrical Supplies 43
WARNING
Improperly connecting the electrical supplies can result
in electrical shock and electrocution. Follow all applicable
electrical codes of the local authority having jurisdiction.
Connecting the electrical components should be performed
only by a licensed professional.
DANGER
●
You must ensure that the boiler is disconnected from the
electrical supply before carrying out any servicing inside
the boiler and, particularly, on the electric terminal strips.
●
If the electrical supply is connected electrical
contact could occur, causing serious damage due to
electrocution.
CAUTION
Label all wires before disconnecting them when you work
on the controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after servicing.
The boiler electrical connections must be made by sufficiently
qualified staff in strict compliance with the sections below and
with any electrical safety regulations applicable at the time of
installation.
Note
The NCB300 boiler has an electrical protection degree
of IPX4D. The electrical connection must be made
via a bipolar switch located on the same premises
as the boiler. The switch must have a minimum pole
separation of 3 mm.
8.1 Accessing the Terminal Strips
To access the PCB where the terminal strips are located, carefully
follow the steps below:
1. Turn off the power supply to the boiler.
2. Unfasten the 2 latches (at the top) and remove 2 screws (at
the bottom) to remove the front cover and gain access to
the internal components.
Note
●
Before connecting the cables to the corresponding
connector terminals, it is essential to thread them
through the cable glands located on the underside
of the boiler.
●
While threading the cables and making the
connections, take special care that no pieces
of cable fall onto the electrical connections or
electronic cards.
●
Make sure you have tightened the cables
sufficiently. It is essential for the boiler to be
grounded.
3. Remove the screw and pull the cover downwards
before connecting the power supply, room thermostat,
OpenTherm, and the outdoor temperature sensor.
8. Connecting Electrical Supplies