The F20 fault code means that there is not enough water in the washer. This may be due to poor water supply.   Please, try the following:

• Press PAUSE/CANCEL twice to cancel the cycle and unplug/disconnect the washer.
• Make sure that hot and cold water faucets are turned on
• Check inlet valve screens for debris
• Make sure the inlet hose is not kinked, clogged or frozen
• Plug the washer back in and restart the cycle.