Navien NPN-120E, User'S Information Manual

Page: 19 / 28

19 Maintaining the Water Heater
4.5 Protecting the Water Heater
from Freezing
CAUTION
Damage due to freezing is not covered by the
Navien limited warranty.
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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.
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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 water heater
to the outdoors. This type of vent system
minimizes air movement within the water
heater.
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This water heater has an optional recirculation
mode that is used for freeze protection. This
mode should prevent the water heater from
freezing, even if the intake air duct is not
vented directly.
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The water heater is designed for indoor or
outdoor installation. However, it should not
be installed outdoors in areas that are prone
to freezing temperatures.
4.4 Cleaning the Inlet Water Filter
To clean the filter:
1. Drain the water heater. Refer to “4.2 Draining the
Water Heater” on page 16.
2. While the filter is removed, rinse it with clean
running water (cold) and, if necessary, scrub it
clean with a brush.
3. Reinsert and tighten the filter.
Cold Water
Inlet Filter
4. Refill the water heater. Refer to “4.2 Draining the
Water Heater” on page 16.