Cheryl T Chino Hills , CA January 28, 2017 Appliance: Whirlpool Washer WFW8300SW01 Whirlpool Washer Wfw8300sw01: Whirlpool duet showing an f20 code. How to replace Washer Water Inlet Valve. The F20 code was low/no water pressure code. I watched a YouTube video and purchased a Water Inlet Valve from Appliance Pros. After my son installed the new part my washer still didn't work. I looked on Google for trouble shooting and the 1st thing it said was turn on both hot/cold water as the washer needs the pressure of the hot/cold water. I had turned off the hot valve because it was leaking. I assumed I could still do cold water loads. 54 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes