Hi
“F” is a fill fault, but by the symptoms given does sound like a base full of water/float activation.
If water is present check usual suspects
1/ Weeping fill valve housing joint (inside cavity)
2/ Weeping from ‘o’ ring/s of heater to sump
3/ Gunged metering unit and/or ribbed hose from unit to sump
4/ 3 or 4 in 1 tablets used in conjunction with rinse aid causing excess foam and overfill