Rainsoft system running continuously

I inherited a rainsoft system with the house I purchased, I believe it's an older apollo system, model AMB 744. The past few days the system has been running continuously, right now it's still plugged in but I have it bypassing the water softner mode so the noise is gone.

Can anyone shed any ideas on what could be the problem? I'm hesitant to call rainsoft, I had them service the system once, the tech was here approx 10mins and it cost me $80, he also tried to sell me an upgraded system.

Thanks for your feedback!