The F21 error on a Whirlpool washer indicates a Long Drain condition where the control board detects water is not exiting the tub within eight minutes. In most service calls, this is triggered by a physical blockage in the pump filter or a failing drain pump motor.
Dealing with an F21 means your machine's sitting there with a tub full of cold, soapy water and it's not going anywhere on its own. Nine times out of ten I pull out a coin or a baby sock from the debris trap and that's the whole fix. If cleaning the filter doesn't solve it, I check the pump motor resistance with a meter because the windings short out from overworking. It's a messy job but almost always a straightforward mechanical repair.
1/4-inch nut driver or hex bit, Phillips #2 screwdriver
What Does the F21 Code Mean?
This fault is your washer saying it's choking on its own drain water. It can come from a faulty pressure switch or control board, but honestly those are rare. I always start at the bottom of the machine because that's where the trouble hides, usually jammed inside the drain housing. Cleared three of these last week alone, and two of them were just a sock and some lint.
Most Likely Causes
Based on aggregated repair data, here is the probability breakdown for this error code:
Debris in pump filter65%
Mechanical pump failure20%
Drain hose obstruction10%
Pressure switch or board fault5%
Symptoms You May Notice
The washer stops mid-cycle with the drum still full of water and F21 flashing on the display.
You can hear the drain pump humming or buzzing continuously for several minutes but no water is actually flowing through the drain hose.
Clothes come out soaking wet and dripping after a supposedly complete cycle because the spin phase got cut short by the drain failure.
There's a puddle forming under or in front of the machine from water that backed up and leaked out around the door boot seal.
The cycle timer seems stuck and keeps stalling, usually hung somewhere in the drain or transition to spin.
Can you reset a Whirlpool washer to clear the F21 code?
After you've fixed the cause, press Pause/Cancel twice to clear the F21 from the display. Then run a Rinse and Spin cycle with an empty drum. Watch the first couple minutes to make sure you can hear water actually moving through the drain hose. If the cycle finishes without the code coming back, you're done. The machine doesn't need any special recalibration after this repair.
Tools Required for Diagnosis
1/4-inch nut driver or hex bitPhillips #2 screwdriverShop vacuum with hose attachmentLow-profile drain pan (under 2 inches tall fits best)Old towels, at least 4-5Needle-nose pliersMultimeter with AC voltage and resistance settingsFlashlight or headlamp
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
ComponentComponent Under Test
Expected Range5–15 ohms
ConditionIf Open (OL) or infinite, replace component.
Replacement Parts
If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.
Part Name
OEM Number
Estimated Price
Drain Pump Assemblyundefined · $30–$75
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$30 – $75
Pump Filter Capundefined · $8–$20
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$8 – $20
Frequently Asked Questions
Can I just reset the F21 code without taking it apart?
You can hit Cancel twice to clear the display, sure. But it'll come right back the next time the machine tries to drain, which is going to be the very next cycle you run. In 15 years of doing this I've almost never seen an F21 just go away on its own. The blockage or burned-out motor isn't going to fix itself. Deal with it now and save yourself the frustration of coming back to a flooded laundry room an hour later.
How much water will come out when I open the pump?
If the tub's full when the code fires, you're looking at 3 to 5 gallons depending on the load size. That's a lot. Don't just crack the filter cap all the way open at once or you'll flood the floor. Turn it slowly, let it drain into your pan, empty the pan, repeat. Using a shop vac to suck water out through the drain hose at the standpipe first will save you a ton of hassle and keep your floor dry. Seriously, do the shop vac step first.
My pump is clean but I still get the F21 code. What now?
If the filter's clear and the impeller spins freely, next check if the pump motor's actually getting power during the drain cycle. Set your multimeter to AC voltage and carefully probe the two pump terminals while running a Drain and Spin cycle. You should see around 120V. If there's power but no pumping, the motor's dead. Also check the pump wiring harness connector because those corrode pretty easily in a wet environment. A new drain pump for this machine runs about $35-55 and it's a pretty easy swap once the toe panel is off.
Is the F21 code the same as the Sud code?
They're related but not the same thing. The Sud or Sd code fires first when the machine detects too many suds, and it'll pause the cycle and try extra rinses to knock the foam down. If it can't clear the suds fast enough and the drain still fails, it escalates to an F21. So if you see both codes back to back in the same session, suds are your root cause. Switch to HE detergent and use less than you think you need. The measuring cap on most detergent bottles is way oversized for these machines.
Does this code mean my control board is bad?
Almost never. Seriously. The CCU being responsible for an F21 is maybe 1 in 50 cases in my experience. It's almost always mechanical, either the pump filter, the pump motor, or the drain hose setup. The pressure switch hose getting pinched is another one people miss. Check all the cheap mechanical stuff first. A control board for one of these machines is $200 or more, and if you replace it before properly diagnosing the root cause you'll have spent a lot of money on the wrong part.
How often should I clean this pump filter?
Honestly, every 3-4 months minimum if you do laundry regularly. Most people never clean it and then wonder why they're getting F21 codes after a few years of ownership. The manual says monthly, which is overkill for most households, but quarterly is realistic and easy to stick to. It takes about 5 minutes once you've done it once and you know where everything is. I've pulled filters out of machines that haven't been touched in 5+ years and the amount of stuff packed in there is genuinely impressive.
Models Known to Experience F21 Errors
This repair applies to most Whirlpool washers with this error code. Common model numbers include: