Nate for Model Number wfw8500sr00 I get an F-20 code on my Duet Sport HT. I've read many forums and blogs and through the service tech guide. The washer enters the drum just fine so no problem with water fill. It usually has a water line about half way up the door glass when the F20 appears. The drain hose and pressure lines have been completely disassembled, cleaned and checked. The pressure switch changes state at the CCU connector PR6. When I check inputs at the CCU PR6 board connector it shows pins 4, 5 and 6 all have continuity to each other. I'm very suspicious the CCU is bad. Another symptom is the washer will get into a rinse cycle and try to fill with water AND intermittently start the drain pump at the same time. I would expect this should be mutually exclusive logic so makes no sense, again pointing to a bad CCU. Once while overriding the pressure switch with an outside pressure while it was filling it threw an F33 code and then shut off. Any further insight would be appreciated as the CCU cost is quite high. Thanks! Nate
Answer Nate, Based on the information provided and the information from the tech data sheet, this issue does sound like it is either a wiring problem between the pressure switch and the CCU. Double check to make sure that there is not corrosion on the terminals at the CCU and pressure switch and verify a good connection. If this checks ok then the CCU would be the issue. Read More... Answered by AppliancePartsPros.com | Friday, October 11, 2013