Explanation: The control board has detected lime
build-up inside the heat exchanger. To prevent
permanent damage to the unit, the unit must be
drained and flushed.
Flushing procedures may need to be repeated for
excessive lime and scale build-up.
*To reset 1L Code, hold down the MIN and MAX
buttons at the same time for 10 seconds
NOTE: Flushing instructions utilize a
submersible utility pump (provided with the
Rheem/Ruud Tankless Flush Kit – RTG20124)