Navien NHB-055 User's Information Manual page 7

2.3.2 Buttons
Using the buttons on the front panel, you can turn on or off the
boiler, monitor the current operation status, and set the values
required for the boiler's operation, such as space heating and DHW
supply temperatures. Refer to the following table for detailed
information.
k
Diagnostics button
For installers only
l
Mode button
Changes the mode.
m
Reset button
Resets the boiler (if an error occurs).
k
l
m
n
Up button
Increases the temperature.
O
Down button
Decreases the temperature.
p
Power button
Turns the boiler on or off.
n
o
p
About the Boiler 7