If your Whirlpool washer is showing the F21 error code, it is experiencing draining problems: the water is not draining properly due to a clogged or damaged drain hose or faulty drain pump. These issues can seriously slow down or completely stop the draining process.

Here are the most likely causes of the problem:

  • The drain hose is blocked with a large foreign object or clogged. Also, a clog may occur in the sewage system.
  • Blocked/clogged drain filter.
  • Blocked, damaged or faulty drain pump (in the latter case it will need to be replaced).

If you see the code flashing on your washer’s display screen, do the following:

  1. Inspect the drain hose (at the washer’s back). Make sure it is not bent or damaged. If necessary, remove it and check it for blockages and clogs. Not unlikely, a large object is stuck down the hose and it is not letting water get out of your washer. Also, check the drain in the wall to ensure it is not clogged.
  2. Unplug the machine, remove the bottom access panel and check the drain pump, filter, and the wiring harness.
  3. Place a tray and/or large towels on the floor to prevent the flooding of your apartment, as there may be water in the system. Remove the drain filter (this is when water may gush out of the system) and check it for debris. If necessary, clean the debris and put the filter back.
  4. Make sure the wiring harness is not damaged. If necessary, check it using a meter.
  5. Make sure the water drain lines around the drain pump are not blocked.
  6. Make sure the water level switch or pressure switch is functioning properly.
  7. When you have checked all the components mentioned above, put the bottom panel back on, plug the washer back in and run a cycle to test it. If the error code is gone and water is draining well, your steps have been successful.