KitchenAid Smoothtop Cooktop Code F21: power supply frequency, and sometimes overheating

What F21 means

On KitchenAid electric radiant touch-control cooktops such as the KECC664BSS, F21 is reported as a problem with the power supply frequency. The cooktop wants a power reset and one minute of monitoring. Some pages describe F21 as cooktop overheating, so if the glass is hot, let it cool first. Owners see the code and the cooking areas stop heating. Do not confuse it with a cookware message; pans have nothing to do with it.

Common causes of F21

A short disturbance in the household power feeding the cooktop
A fluctuation caused by a generator or poor utility power
A control that misreads the supply frequency
Heat in the cooktop, if your unit uses the overheating reading

✓ One safe check you can try

1. Make sure no cooking area is on, and let the glass cool. 2. Flip the cooktop breaker off, count to sixty, and flip it on. 3. Watch the display for one full minute. 4. Call us if F21 appears again after the reset. 5. Keep pans off the glass while the code is displayed.

! Why to stop there

The supply and the control board both need meter checks.
Those tests are done on live circuits, so they are not for owners.
You see the price in writing first, and our repairs carry a 30-day warranty.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Cooktop codes

FC RRKitchenAid Induction Cooktop Code FC RR: the right rear zone does not respond H - Residual HeatKitchenAid Induction Cooktop H: Residual Heat Indicator Indicator or Display FlashingKitchenAid Induction Cooktop Flashing Display: Keys Held Down Indicator or Hot Light OnKitchenAid Smoothtop Cooktop Hot Light On: Control Still On or Element Hot LockKitchenAid Induction Cooktop Message "Lock": Control Lock Is Active Other F CodeKitchenAid Induction Cooktop Other F Code: Touchpad, Power Board or Wiring Performance Boost Flashing - Power Level ChangesKitchenAid Induction Cooktop Performance Boost Flashing: power levels change between zones F61KitchenAid Induction Cooktop Code F61: a wide net of touch control, module, wiring and supply

F21F21 questions

Can my home power really cause F21?

Yes. If the frequency or quality of the supply wanders, the control may raise the code. A flicker, a failing breaker or a generator feed are examples worth mentioning.

Why does F21 sometimes mean overheating?

A few KitchenAid pages treat F21 as overheating on some radiant and induction cooktops. So cool the cooktop first, then reset. If both fail, we test the supply and the control.

Is the reset step really needed?

Yes. It is how the cooktop re-reads the power. If the code does not return in a minute, the supply was probably the cause of a one-off event.