The F20 fault code means that the machine is not filling with water properly. To solve the problem, try this:
Press Pause/Cancel twice to stop the cycle, switch off the machine and disconnect it from the mains.
Make sure that:
- Both hot and cold water faucets are turned on
- The screens at the inlet hose connection are not blocked
- The water inlet hose is not frozen, blocked, kinked or obstructed in any other way
After that, plug the appliance back in and restart the cycle. If the error is still there, use professional help.