Debbie D Maynard , AR March 19, 2022 Appliance: Whirlpool Undercounter Dishwasher DU930PWSB1 Whirlpool Dishwasher Du930pwsb1: Whirlpool dishwasher not draining. How to replace Check Valve Assembly. I purchased both the check valve and impeller kit. I watched the videos as I worked. This was great!! I have never worked on a dishwasher and both of these videos were exactly right. Dishwasher is back in good working order. I am very, very happy! Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes