Product review (4 stars): Fixed F20 error, and fabric softener dispensing issue
Just as afaviator reported on 6-26-14, I thought my F20 error was caused by the FLOW METER. It wasn't. About the same time the F20 errors started, the fabric softener stopped dispensing. I recently ordered and installed a new INLET VALVE (where the hoses connect to the back of the washer; Whirlpool front loader WFW9400SW01), and a new PRESSURE SWITCH. I'm now convinced it was the INLET VALVE alone causing the F20 errors AND the fabric softener dispensing issue. As afaviator reported, it appears the old inlet valve must have been clogged internally and restricting proper flow since the little screens were free of debris. The fabric softener is now dispensing and we hope the F20 errors have ceased. If you are having similar issues, try replacing the inlet valve first. The total cost for all three items was slightly more than $100. Ordering was easy and parts arrived in a timely manner. I too recommend replacing the original supply hoses with the steel reinforced (braided) hoses.