System Fill Connection - Navien NCB-180 Installation & Operation Manual

3.4 System Fill Connection

Before filling the boiler, remove the air vent cap to allow the
system to fill properly. Replace the cap when the system is full.
Ensure that the vent cap is re-installed before testing
Note
or operating the system.
3.4.1 Built-in Water Fill Connection
Navien NCB boiler is equipped with an auto-feeding water
connection and motorized feeding valve. Therefore, installation
of additional system water fill connection is not necessary in
most cases. See the following figure for an example of a water fill
installation using the built-in connection.
Backflow Preventer
Air Vent Cap
Make-up Water
3.4.2 External Water Fill Connection
External water fill connection may be installed on the system
piping if it is required for specific applications. See the following
figure for an example of external water fill installation on the
system piping.
Pressure Relief Valve
Air Separator
Circulator
To System
Make-up
Water
From
System
Expansion Tank
Installing the System Piping 25