- Select three numbers to serve as your new combination. Horizon advises that you not use numbers ending in "0" or "5" and do not choose numbers that increase in sequence (such as 38-53-79), as these combinations may be easier to guess.
- Open the safe by entering the current combination. Turn the dial counterclockwise three times, stopping with the opening index on the first number of the combination the fourth time. Turn the dial clockwise twice, stopping on the third rotation when the opening index is lined up with the second combination number. Turn the dial counterclockwise once, stopping on the second rotation when the opening index is aligned with the third combination number.
- Turn the dial clockwise slowly until you hear the bolt retract. Pull the door open.
- Enter the combination again as though you were opening the safe, but use the changing index instead of the opening index. This will trigger the lock to accept a combination change.
- Hold the dial firmly with the changing index lined up with the final number of the old combination. Insert the change key in the keyhole located on the back of the lock, on the inside of the door. Make sure the key is fully inserted before continuing.
- Turn the key one-quarter turn to the left to set the lock into change mode. Hold the key in this position and enter the new combination, turning the dial counterclockwise three times and stopping with the changing index on the first number during the fourth rotation.
- Enter the remaining two numbers of the new combination with the appropriate number of turns, using the changing index. This will set the new combination into the lock. Hold the dial firmly in place on the last number, turn the change key one-quarter turn back to the right and remove the key.
- Test the new combination at least twice with the opening index before closing the safe; you must hear the bolt unlatch to know that the combination change has gone into effect.
- All Horizon safes are shipped with the same initial opening instructions. If you have not yet programmed your safe, turn the dial counterclockwise four times, stopping on the fourth rotation with the opening index resting on the number 50. Slowly turn the dial clockwise until you hear the bolt unlock.