How to fix a Dishlex Global 500?

My Dishlex Global 500 when tuned on continues to pump even though there is no water to pump out. The message on the control panel shows OF meaning what I believe is meant to be over full. This cannot be the case as the solenoids are simply not opening up to let in water. I have replaced one solenoid only, and swapped it around on both the hot and the cold but to no avail. I have check the foam floats that trigger the micro switches also.
Any ideas what I could try next?