Michael F West Chester , PA December 22, 2025 Appliance: Whirlpool Washer WFW9600TW01 Whirlpool Washer Wfw9600tw01: F 21 error failed drain pump. How to replace Washer Drain Pump Assembly. Order the part of ApplianceParts Pros.com, arrived in one day and followed the basic instructions for replacing the part after watching a YouTube video. Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes