Protecting The Boiler From Freezing; Maintenance Schedules - Navien NFC Series User's Information Manual

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
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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
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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
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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.
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To ensure that the boiler does not freeze, follow these guidelines:
Do not unplug the power supply cord, except for routine
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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.
Do not close the gas valve, except for routine maintenance, as
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this will limit additional freeze protection.
If the boiler will not be used for an extended period, drain
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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.
If hot water will not flow and you suspect that the
Note
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boiler is frozen, contact an authorized technician or
licensed professional.
This boiler requires very little maintenance, however
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a qualified technician should inspect the boiler at
the beginning of every heating season and/or when
there is a problem.

4.5 Maintenance Schedules

Owner maintenance
Check the boiler area is free of
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combustible/flammable materials and
air contaminants.
Daily
Check the pressure/temperature
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gauge for signs of higher than normal
pressure.
Visually inspect the vent piping for
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signs of leakage and blockage.
Monthly Visually inspect the burner flames.
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Inspect the condensate trap and the
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PVC fittings.
Periodically Test the LWCO for proper operation.
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Inspect boiler piping (gas and water)
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for leaks.
Every 6 months
Test to make sure the relief valve is
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operating normally.
Non-heating Shut boiler down (unless boiler is used
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season for domestic hot water).
Service technician (See the following instructions)
General:
Address reported problems.
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Inspect interior; clean and vacuum if
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necessary.
Clean condensate trap and fill with
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fresh water.
Check for leaks (water, gas, flue,
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condensate).
Verify flue and air lines in good
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condition and sealed tight.
Check system water pressure/system
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piping/expansion tank.
Check control settings.
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Annual Start-up
Check ignition and flame rod (clean and
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reposition).
Check wiring and connections.
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Inspect flame (stable, uniform).
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Inspect flame signal.
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If combustion or performance indicate
need:
Flush heat exchanger.
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Remove and clean air intake filter.
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Remove and clean space heating
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strainer.
Remove and clean inlet water filter.
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Maintaining the Boiler 15