It has been my historical experience, having maintained a few hundred of these devices over time, is that moment such a thing starts to go funny, replace it entirely.

Batteries *must* be replaced quarterly - sure, the literature 'suggests' annually, but a low battery will play merry hell with the internal programming, however the manufacturer might suggest otherwise.

Given that in my applications, lives, quite literally, depended on the reliable operation of these locks, I took no chances.

Peter Wieck
Melrose Park, PA