Nautilus NH-1800 Operator's Manual page 30

NH-1800
5.1.2 How to open the mechanical combination lock
Make sure that this lock would be set 50-25-50 as factory default setting.
1) Turn to the counterclockwise for more than four times and set to "50."
2) Turn to the clockwise and stop at "25" at the third times.
3) Turn to the counterclockwise and stop at "50" at the second times.
4) Turn to the clockwise until the dial does not move any more.
Note: The center scale mark is used to open the safe unit
5) The safe door will open when turning the handle to counterclockwise.
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5. Operating Instructions