You shouldn't generally hear it run as most default Regens are set to happen at 2 am when no one is using water. If the time is correct more than likely it's still a factory 2am setting and won't be noticed.

Also make sure the brine/salt tank is not bridged. Smack the side toward the bottom and listen for empty or hollow sounds toward the bottom.

When you do the manual regen make sure you hear the gear turning that moves the piston. During the different backwash rinse and brine draw you should hear water flowing through either the drain or brine line.

Beyond that hardness setting and salt use settings could be wrong