Navien NR-180(A) Operation & Installation Manual page 78

Once a temperature is selected, the unit will operate at that selected temperature until
that temperature is changed.
A Navien Water Heater will not provide hot water instantly at the hot water fixture
unless an "A" series unit in used with "external recirculation" mode.
Any existing cold water in the hot water lines must be purged before hot water
can reach the hot water fixtures.
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When a hot water faucet is opened, the
unit will automatically start. The GREEN
LED indicator will illuminate indicating
normal operation.
will appear on the display.
When the water heater is "condensing",
the "Energy Saving" indicator will appear
on the monitor.
Energy saving indicator.
When the hot water faucet is closed,
the water heater turns off automatically.
The GREEN LED indicator turns off.
will disappear from the display
(unit : °F)