Filling The System; Testing The Water System - Navien NHB H Series Installation And Operation Manual

3.3 Filling the System

Before filling the boiler, completely unscrew and
remove the air vent cap to enable the system to fill
properly. Also, loosen the vent screws on the system
and boiler pumps to prevent the air from being
trapped inside the pumps.
If the air vent cap is only partially
Note
loosened, the air vent may not allow for
the boiler to fully purge. The cap must be
completely unscrewed and removed to
complete the procedure.
Replace the air vent cap and tighten the vent screws
on the pumps when the system is full.
Vent
Screw
NOTICE
Ensure that the vent cap is re-installed and
●
the vent screws on the system and boiler
pumps are properly tightened before testing
or operating the system.
Ensure that the pressure relief valve is closed
●
before testing or operating the system.
26 Installing the System Piping
Air Vent Cap
3.3.1 Make-up Water Connection
An external make-up water connection is required.
The illustration below shows an example of an
external water supply connected to the system
piping.
Air Separator
From
System
Expansion Tank

3.4 Testing the Water System

WARNING
To prevent death, serious injury or property
damage:
Ensure that the boiler is full of water before
firing the burner. Operating the unit without
completely filling it could cause abnormal
operation of the boiler and potential product
damage. Such damage is not covered by the
warranty.
Perform a leak test after installing the boiler's water
system to make sure that the system has been
installed properly. Follow the instructions below to
perform a fill test on the water system.
Pressure Relief Valve
Pump
To System
Make-up
Water