Whirlpool Dryer AF Error — Check Vent Air Flow Fix

What it means

Whirlpool dryer AF (some panels show 'Check Vent' instead) is the restricted-air-flow code.
Whirlpool's exact wording: 'an AF (Restricted Air Flow) error code indicates that the lint screen or vent is clogged; the vent may be crushed, kinked or have too many turns.'
The dryer keeps running with AF displayed — but drying times will be much longer and the heating element is working hard.

Affected Models

Whirlpool WED4815 / WED4850 / WED5000 series electric dryers
Whirlpool WED7120 / WED8120 / WED9620 Cabrio series
Whirlpool WGD4815 / WGD5000 / WGD7120 series gas dryers
Whirlpool Compact Heat Pump dryers (WHD862, WHD560)
Same F+E codes appear on Maytag, KitchenAid, and Amana dryers (shared platform)

Common Causes

Lint screen clogged — restricts airflow at the source
Exhaust vent crushed or kinked behind the dryer
Vent run too long or with too many 90° elbows
Exterior vent hood blocked by lint, bird's nest, or stuck-shut flap
Indoor lint trap (if installed) full

How to Fix It

Run Whirlpool's hand-test for air flow.

Whirlpool's exact published test: 'Run the dryer for 5-10 minutes and hold your hand under the outside exhaust hood to check air movement. If the air movement is less than a hair dryer on high speed, clean the lint from the entire length of the system and the exhaust hood.'
That comparison to a hair dryer is your benchmark.
Clean the lint screen.

Pull the lint screen out and clear all visible lint.
If you use dryer sheets, hold the screen up to a light — if you can't see clearly through the mesh, dryer sheet residue is blocking airflow that you can't see.
Rinse under warm running water and let it dry fully before reinstalling.
Check the vent run between dryer and wall.

Whirlpool: 'check whether the vent run from the dryer to the wall is crushed or kinked, confirm that the vent run from the dryer to the wall is free of lint and debris.'
Pull the dryer out an inch and inspect.
Replace any crushed flex duct sections.
Clear the exterior vent hood.

Whirlpool: 'confirm that the exterior vent exhaust hood is free of lint and debris.'
Walk outside and check the flap — it should open freely when the dryer is running.
Bird's nests in spring and lint mats after years of use are the common culprits.
Restart with a Timed Dry cycle.

Whirlpool: 'Select a Timed Dry heated cycle and restart the dryer.'
If the dryer completes the cycle without AF reappearing, the issue is resolved.
Hire a venting specialist for long runs.

Whirlpool: 'If the message persists, have your entire home venting run cleaned. Contact a venting specialist.'
Long runs (over 25 feet), runs through walls, and roof terminations need professional drill-powered brushes — household vacuums don't reach the buildup.

When to Call a Professional

AF is owner-fixable through cleaning.
Only schedule service if the lint screen is clean, the full vent run is clear, the exterior hood opens freely — and AF still appears.

Frequently Asked Questions

How is AF different from F4E3?

Both are Whirlpool's restricted-air-flow code — same fault, different display.
AF appears on older Whirlpool dryers with simpler 3-character displays.
F4E3 appears on newer Whirlpool dryers with dot-matrix displays that can render the full F+E format.
Whirlpool's troubleshooting steps for both are identical, and both reference the same vent-cleaning procedure.