Welcome. My name is XXXXX XXXXX would be glad to assist.The lock has a re lock time of 30 seconds maximum, and should always re-lock itself after unlocking.I would do a test:Have 2 individual entrants. One enters the code and unlocks the door and enters.Wait for the door to re-lock.Then the next one enters the code and unlocks the door and enters.Wait to see if the door re-locks.Now, after waiting 10 minutes or so.Do the test again with 2 people.See if it works properly again with 2 people.What we are trying to see here, is if the batteries are fairly low.If batteries are still good but low, what can happen, is the door unlocks and re-locks several times, but at that point there isn't sufficient battery voltage to re-lock again.After letting batteries wait a while, they tend to get back to the normal voltage.Testing with 2 people instead of 3 will help to evaluate if the batteries do the same thing in sequential entries of 2 or not.The unit should re-lock in any situation if there is sufficient battery voltage, so it may very well be a bad lock.Testing from above should prove or disprove.
If it fails the 2nd time of testing, I would venture to get some fresh batteries.Those are the only two items to prevent a re-lock, weak batteries or bad unit.The re-lock maximum time is 30 seconds.Just reply for any clarification. thanks