Unit is functioning on the back up freeze timer.
Cause:
Float Switch stuck in the up position.=Empty sump, remove float switch (Carefully and watch the small pin that keeps the float inside). Clean and reassemble.
Water Valve leaking by:=Only fix is to replace. Turn unit off. If water continues to run in and overflows the sump, it's leaking.
The other things that can cause this requires a qualified tech as it is a refrigeration problem.

Hope this gets it for you.