Protecting The Boiler From Freezing - Navien NFB-175H User's Information Manual

4. Remove the screw that secures the air intake
filter (the filter is located at the top left of the
boiler).
5. Pull the filter out of the boiler.
6. Remove the filter from the plastic assembly.
Dust and rinse it with clean running water.
7. Allow the filter to dry completely.
8. Place the filter assembly back into the boiler and
secure it with the screw.
9. Replace the front cover.
10. Reconnect the power supply to the boiler.
11. Press the Power button (
to turn on the boiler.
16 Maintaining the Boiler
) on the front panel
4.4 Protecting the Boiler from
Freezing
CAUTION
Damage due to freezing is not covered by the
Navien limited warranty.
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.
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.
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.
The boiler is designed for indoor installation
●
only.
To ensure that the boiler does not freeze, follow
these guidelines:
Do not unplug the power supply cord, except
●
for routine maintenance. The boiler has a freeze
protection function that requires power. The
freeze protection function will operate regardless
of whether or not the power is turned on or in
standby mode, as long as the power supply is still
connected.
Do not close the gas valve, except for routine
●
maintenance, as this will limit additional freeze
protection.
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.