Boss RC-3 Mode D'emploi page 3

Owner's Manual
* This device contains demo phrases (90–99). Once you delete these, they
cannot be recovered. Please back them up as described in "Backing up to
your computer" (p. 14).
* This device will enter Sleep mode (power conservation mode) when ten
hours have elapsed since the last operation, or since the last audio input
while in Stop mode.
If you want to prevent the device from entering Sleep mode, hold down the
pedal while you turn on the power, and continue holding down it down for
five seconds (p. 18).