Thank you !
Sorry I do not work on Sundays.
Ok the F-20 as it appears you know if a NO WATER DETECTED ENTERING MACHINE OR PRESSURE SWITCH TRIP NOT DETECTED.
And yes the couple of inches of standing water in the rear of the tub is normal.
Now you have checked the water level pressure switch water inlet valve screens pressure switch hose .which is fine .
But this machine senses the amount of water that is going into the machine via the flow meter in the water inlet side from the water valve to the dispenser .
This device has a small paddle wheel in it ,if it is not turning (possibly from a grain of sand of calcium) in the water it will not turn thus it will not tell the control board that water is entering the machine .
The flow meter is easy enough to test .remove it`s wire harness and remove it from the line.
And with a volt ohm meter you can test if for continuity as the wheel turns .
BUT only breath into the flow meter if you (blow hard) into it that can cause it to spin so fast that it will show it as not having continuity ,so just a nice smooth breath.
Let me know what you find
I`m normally on line from 10:00 -5 P.M. EST. mon-sat.