Connecting The Power Supply - Navien NHB Series Installation & Operation Manual

7. Connecting the Power Supply

WARNING
Improperly connecting the power supply can result in electrical
shock and electrocution. Follow all applicable electrical codes
of the local authority having jurisdiction. In the absence of
such requirements, follow the latest edition of the National
Electrical Code (NFPA 70) in the USA or the latest edition
of CSA C22.1 Canadian Electrical Code Part 1 in Canada.
Connecting the power supply should be performed only by a
licensed professional.
When connecting the power supply, follow these guidelines:
Do not connect the electric supply until all piping and gas
piping is complete and the boiler has been filled with water.
Do not connect the boiler to a 220-240V AC power supply. Doing
so will damage the boiler and void the warranty.
Connect the building wires 'L' , 'N' , 'G' to the terminal block
according to the printed specifications on the boiler PCB. The 'G'
terminal should be connected to the building ground.
L
The rated current of the wires is 12 A.
Note
When connecting an external pump to the boiler, connect it to
the external pump terminal of the boiler PCB.
Connect the wires referring to the following table. The pump
ground should be connected to the boiler and the building
ground.
For details, refer to the "12.2 Wiring Diagram" on page 116.
1. Boiler
N-phase
Pump
2. Building
L_IN-phase
wire
3. Boiler
L_IN-phase
Pump
The maximum current of the pump is 5A.
Note
64 Connecting the Power Supply
N G
1. Building
<-> N-phase
wire
<-> 2. Boiler PCB L_IN-phase
L_OUT-
<-> 3. Boiler PCB
phase
We recommend using a surge protector to protect the boiler
from power surges.
If there is a power failure in cold weather areas, the freeze
prevention system in the boiler will not operate and may result
in the heat exchanger freezing. In cold areas where power
failures are common, you must completely drain the boiler
to prevent damage if power cuts last for extended periods.
A battery back-up (available at most computer retailers) may
be used to supply hot water during power outages. Damage
caused by freezing is not covered under warranty.
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.