Electrolux F21 microwave: what it means & what to check

What F21 actually means

The appliance has found it is already too warm inside to start a programme, so it has shut itself down until it cools.

On this model the control board takes a temperature reading before it will allow a cycle to begin. If that reading is above roughly 40°C, the user interface sends a shut-off command and flags F21 instead of starting — you will usually see it either as an error or as a pop-up message on the display. It is a protective stop rather than a component failure, and the message stays on screen until the interface is switched off.

What F21 looks like on a Electrolux microwave

Most people find this page having searched for what the machine is doing rather than the code itself. On a Electrolux microwave, F21 usually shows up as one or more of these:

Microwave door won't open
Door won't lock or click shut
Door lock light flashing
Door stuck shut with the load inside
Won't start even with the door closed
Not heating the water
Washing coming out cold
Cycle takes far longer than it should

Recognise any of those? That is this fault, and the rest of this page explains what causes it and what you can check yourself.

What usually causes it

The cavity is still hot from a previous cooking or grilling cycle
Heat rising from a hob or a neighbouring oven built into the same housing
Blocked or restricted ventilation around the appliance, so heat has nowhere to go
A cooling fan that is not running long enough after use
A faulty temperature sensor or control board reading a high temperature that is not really there

What you can safely check yourself

Work through these in order. Anything beyond this — panels off, testing parts, anything to do with the wiring — is an engineer's job, and not one to attempt with the machine plugged in.

Leave the door open and let the appliance cool for an hour or so, then try again
Check the vents and the gap around the appliance are clear of tea towels, packaging or anything stacked against it
Switch off at the wall for a minute, then back on, once it has cooled
If it appeared straight after heavy oven or hob use nearby, wait until everything has cooled before starting a programme

Which Electrolux models show F21

F21 means the same thing on this model. If yours is not listed, the explanation above still applies — the code is set by the control board, not the model number.

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Common questions about Electrolux F21

What does F21 mean on a Electrolux microwave?

The appliance has found it is already too warm inside to start a programme, so it has shut itself down until it cools. On this model the control board takes a temperature reading before it will allow a cycle to begin. If that reading is above roughly 40°C, the user interface sends a shut-off command and flags F21 instead of starting — you will usually see it either as an error or as a pop-up message on the display. It is a protective stop rather than a component failure, and the message stays on screen until the interface is switched off.

Can I fix Electrolux F21 myself?

There are 4 checks you can safely do yourself first.

Leave the door open and let the appliance cool for an hour or so, then try again.
Check the vents and the gap around the appliance are clear of tea towels, packaging or anything stacked against it.
Switch off at the wall for a minute, then back on, once it has cooled.
If it appeared straight after heavy oven or hob use nearby, wait until everything has cooled before starting a programme.

This sometimes clears with those checks. If it comes back, it needs looking at properly.

How much does it cost to repair Electrolux F21?

£66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Tried the checks and it's still showing F21?

This sometimes clears with the checks above. If it comes back, it needs looking at properly. Then it wants someone who can open it up.

What it costs, before you call: the price is the same whatever the fault turns out to be — £66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Our own engineers, not a call centre. We cover Nottinghamshire, Derbyshire and Leicestershire — most microwave faults are seen same day or next day.

Call 0115 648 0929 Book online — postcode and number is all we need

Outside our area? The explanation above still stands — take it to a local engineer and tell them the code. Knowing it saves them time and you money.

Other Electrolux microwave codes

All Electrolux fault codes and repairs →

Written by the engineers at ASAP Repairs, 0115 648 0929. We repair these machines for a living in Nottinghamshire, Derbyshire and Leicestershire.

Electrolux F21 error — microwave