We continually observed a ‘NF’ code on our Samsung WF218ANW/XAA washer at the 16 minute mark of the wash cycle. After cleaning the screens out on the OEM valves and changing the water hoses with no solution, all signs pointed to the fill valves. Since I was opening the washer up and prying it out of the closet where it sits, I replaced both the hot and cold valves. The repair couldn’t be easier and I’m happy to report the problem is solved.