Navien NHB-150, User Manual, Page: 14 / 24

14 Maintaining the Boiler
4.5 Maintenance Schedules
Owner maintenance
Daily
Ɣ Check the boiler area is free of
combustible/flammable materials and
air contaminants.
Ɣ Check the pressure/temperature
gauge for signs of higher than normal
pressure.
Monthly
Ɣ
Visually inspect the vent piping for
signs of leakage and blockage.
Ɣ Visually inspect the burner flames.
Ɣ
Inspect the condensate trap and the
PVC fittings.
Periodically
Ɣ
Test the LWCO for proper operation.
Every 6 months
Ɣ Inspect boiler piping (gas and water)
for leaks.
Ɣ
Test to make sure the relief valve is
operating normally.
Non-heating
season
Ɣ Shut boiler down (unless boiler is used
for domestic hot water).
Service technician (See the following instructions)
Annual Start-up
General:
Ɣ Address reported problems.
Ɣ
Inspect interior; clean and vacuum if
necessary.
Ɣ Clean condensate trap and fill with
fresh water.
Ɣ
Check for leaks (water, gas, flue,
condensate).
Ɣ Verify flue and air lines in good
condition and sealed tight.
Ɣ
Check system water pressure/system
piping/expansion tank.
Ɣ Check control settings.
Ɣ
Check ignition and flame rod (clean and
reposition).
Ɣ
Check wiring and connections.
Ɣ Inspect flame (stable, uniform).
Ɣ
Inspect flame signal.
If combustion or performance indicate
need:
Ɣ
Flush heat exchanger.
Ɣ Remove and clean air intake filter.
4.4 Protecting the Boiler from Freezing
CAUTION
Damage due to freezing is not covered by the Navien limited
warranty.
Ɣ
Freezing damage is most likely to occur due to back drafting
caused by negative pressure in the building. This is not a
manufacturing defect, and therefore, Navien will not warrant
any damages due to freezing. The installer is responsible for
ensuring that there is sufficient make-up air to avoid such
a situation and the owner is responsible for ensuring that
protection against freezing is maintained.
Ɣ To avoid freezing issues, we strongly recommend the use of
a direct vent exhaust and intake system. Your installer should
ensure that the exhaust vent pipe and the air intake pipe are
both connected directly from the collars on the top of the
boiler to the outdoors. This type of vent system minimizes
air movement within the boiler.
Ɣ This boiler has an optional recirculation mode that is used for
freeze protection. This mode should prevent the boiler from
freezing, even if the intake air duct is not vented directly.
Ɣ
The boiler is designed for indoor installation only.
To ensure that the boiler does not freeze, follow these guidelines:
Ɣ
Do not unplug the power supply cord, except for routine
maintenance. The boiler has a freeze protection function that
requires electricity. The freeze protection function will operate
regardless of whether or not the power is turned on or off, as
long as the electric supply is still connected.
Ɣ
Do not close the gas valve, except for routine maintenance, as
this will limit additional freeze protection.
Ɣ
If the boiler will not be used for an extended period, drain
the boiler.
If the power or gas supplies must be disconnected for an
extended period, drain the boiler. Freezing damage may occur if
there is water remained in the boiler in cold weather.
Note
Ɣ
If hot water will not flow and you suspect that the
boiler is frozen, contact an authorized technician or
licensed professional.
Ɣ
This boiler requires very little maintenance, however
a qualified technician should inspect the boiler at
the beginning of every heating season and/or when
there is a problem.