Protecting The Water Heater From Freezing - Navien NPE-210A Operation Manual

4.6 Protecting the Water Heater 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 water heater to the outdoors. This type of vent system
minimizes air movement within the water heater.
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.
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.
To ensure that the water heater does not freeze, follow these
guidelines:
Do not unplug the power supply cord, except for routine
maintenance. The water heater 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
this will limit additional freeze protection ("A" model only).
If the power or gas supplies must be disconnected for an
extended period, drain the water heater. Freezing damage may
occur if there is a loss of power or an interruption in the gas
supply to the water heater.
If the water heater will not be used for an extended period,
drain the water heater.
14 Maintaining the Water Heater
If hot water will not flow and you suspect that the water heater is
frozen, follow these steps:
1. Press the Power button on the front panel to turn off the water
heater.
2. Close the gas valve.
Gas
Valve
3. Open the hot water faucet that is closest to the water heater.
4. Use a hair dryer or a portable electric heater to heat up both
the primary and secondary Heat Exchangers.
5. Check every few minutes to see if water is running at the open
faucet.
6. When the water starts flowing again, check the water heater
and piping for leaks. If you detect any leaks or the water heater
is not operating properly, contact an authorized technician or
licensed professional
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