FixByModel
F21

Whirlpool F21: Long drain: water draining too slowly

F21 appears when the washer takes longer than about eight minutes to drain the tub. It points to a restriction in the drain path rather than a wash problem.

DIY fix

By the FixByModel editorial team · Verified 2026-09 · Researched against manufacturer support & repair references (below)

Most likely causes

  1. Clogged drain pump filter (coin/lint trap)
  2. Kinked or clogged drain hose
  3. Excess suds from too much or non-HE detergent
  4. Blocked drain pump impeller or foreign object in pump
  5. Clogged household standpipe or wall drain
  6. Faulty water-level pressure switch or drain pump
The drain path — check in this order
1Drum
2Sump hose
3Filter
4Drain pump
5Drain hose

Schematic illustration of a typical washing machine — not your exact model.

Before you start — unplug the appliance and turn off the water supply. You'll be working near water and electrical parts, and drained water can be hot. If a step involves the pump, wiring, or opening the cabinet and you're unsure, stop and call a qualified technician.

Step-by-step fix

1ResetUnplug the washer for a few minutes, or press PAUSE/CANCEL twice, then restart to see if the code clears.
2Check suds/detergentIf it followed heavy detergent use, run a Rinse & Spin with no soap and switch to the correct HE dose.
3Inspect the drain hoseStraighten any kinks and confirm the hose and the wall standpipe are not clogged.
4Clean the drain filterOpen the lower front access panel, remove the drain pump filter/coin trap and clear lint, coins, and debris; flush with warm water.
5Check the pumpInspect the drain pump impeller and wiring harness for blockage or damage.
6Service if unresolvedIf drainage is still slow, the drain pump or pressure switch may need replacement by a technician.

Still showing F21?

If you’ve worked through every step and F21 keeps returning, an internal part likely needs testing and replacement. That’s a job for a qualified appliance technician, who can measure the suspect part against the service-manual spec before replacing it.

Which models this applies to

Whirlpool washing machines. Front-load Whirlpool washers, notably Duet and similar models using the older F## code format.

FAQ

What does Whirlpool F21 mean?

Long drain: water draining too slowly. F21 appears when the washer takes longer than about eight minutes to drain the tub. It points to a restriction in the drain path rather than a wash problem.

What causes Whirlpool F21?

The most likely cause is clogged drain pump filter (coin/lint trap). Other causes include Kinked or clogged drain hose; Excess suds from too much or non-HE detergent; Blocked drain pump impeller or foreign object in pump; Clogged household standpipe or wall drain; Faulty water-level pressure switch or drain pump.

Can I fix Whirlpool F21 myself?

Usually yes. Start by working through the steps above, beginning with: unplug the washer for a few minutes, or press pause/cancel twice, then restart to see if the code clears.