Oven not heating up
An oven that lights up, accepts a temperature and stays cold has usually not failed. Something is stopping it heating, and three of the causes cost nothing.
What it usually means
Separate the two halves of an oven before you diagnose anything. There is the part that makes heat — one or more elements — and the part that decides whether they are allowed to, which is a chain of a clock, a function selector, a thermostat and a safety cut-out. A cold oven with a working display is nearly always the second half, and that is the good news, because most of it is free.
Start with the clock, because on a great many built-in ovens it is an interlock rather than a convenience. After a power cut the display flashes, and until the time is set the oven will not heat at all. The same applies to an automatic cooking programme somebody set weeks ago and never cleared: the oven is obediently waiting for a start time that has passed. Manufacturers document this, and Hotpoint are explicit that on some of their models the clock is a condition of the oven running.
Next is demo mode. It exists so a shop can light an appliance up on the shop floor without heating it, and it gets switched on at home by an unlucky sequence of button presses. Everything works, the display responds, the fan runs, and nothing ever gets warm. AEG say plainly that this is possible on theirs, and it is more common than anyone expects.
Only then look at heat. On a fan oven the element is a ring behind the back panel, around the fan; on a conventional oven there are two, top and bottom. That distinction matters diagnostically: an oven with two elements where one has failed does not go cold, it goes slow, so food that takes half as long again to cook is a different symptom from an oven that never warms. And the grill is nearly always its own element on its own circuit, which makes it a free test — a grill that works proves the supply, the clock and the controls, and puts the fault squarely on the oven element or its thermostat.
Behind both is a safety cut-out that removes power if the cavity gets too hot, usually because a fan has stopped. On some models it resets itself when cool and on others it is a one-shot device that has to be replaced, and either way it has tripped for a reason worth finding rather than merely resetting.
How to narrow it down
Work through these in order.
Is the clock flashing, or has the time never been set?
Set the time and date properly and try again, and check for a cooking programme or auto timer still loaded. This is the first thing to rule out because on many ovens it is a genuine interlock: the appliance will light its display, beep at you and refuse to heat until the clock is running.
Does the grill work?
Put it on for two minutes and look for the element glowing. A working grill proves there is power, the clock is not blocking anything and the controls are functioning, which narrows a cold oven to its own element, its thermostat or the cut-out. A dead grill as well points upstream at the supply or the board.
Does the fan run when you set a temperature?
On a fan oven, listen at the door. A fan turning with nothing getting warm points at the element behind the back panel. Silence from the fan is more serious in a different way: the element is not allowed to run without it, so the oven will either refuse to heat or trip its safety cut-out shortly after starting.
Is it cold, or just slow and undercooking?
These are two faults, not one. Completely cold points at a single heat source that has failed or is not being switched on. Food taking noticeably longer, or browning on one side only, points at one of two elements having gone, or at a thermostat that has drifted low — worth checking with a cheap oven thermometer before anyone is called.
Is there anything on the display it does not usually show?
A word like Demo, SAFE or Loc, small squares, a padlock or a code all mean something specific, and none of them means the oven is broken. Look up exactly what is showing rather than clearing it, because half of these are settings you can undo in ten seconds once you know what they are.
Has the cooker switch or the breaker been off?
Built-in ovens are usually wired to a cooker circuit through a switch on the wall rather than plugged in, so check that switch is on, then check the consumer unit. An oven that has lost power will also have lost its clock, which brings you back to the first question on this page.
Did it stop right after a self-clean cycle?
A pyrolytic clean runs the cavity to around 500 degrees and is the hardest thing an oven ever does to itself. Elements, thermostats, door locks and cut-outs commonly fail during or just after one, so if the timing lines up, say so when you book: it points an engineer at a much shorter list.
Codes commonly shown with this
- F1AEGOne code, two published meanings. On a pyrolytic AEG oven it is about the door not closing. On a non-pyrolytic one AEG call it an electronic fault and send you straight to service.Get it checked
- DemoAEGThe oven lights up, accepts settings and never heats. AEG admit demo mode can switch itself on after a power cut, and the code to switch it off is 2 4 6 8.Usually simple to fix
- Er 32BekoOven heating errors, covering Er 32 to Er 41. This is the band for an oven that lights up, whirs and never gets hot.Get it checked
- Not heatingBoschBosch answer this by naming the heating element and telling you to book a repair. Their own manuals give three free causes their website leaves out entirely.Get it checked
- Clock flashingHotpointOn some Hotpoint ovens the clock is an interlock, not a convenience. Until the time of day is set, the oven will not cook at all.Usually simple to fix
- F134MieleThe sensor is reading the cavity as too hot. Miele give no owner remedy for this one, and they conspicuously withhold advice they publish for a related code.Stop — call an engineer
When it is urgent
Take care
What it costs
Typical repair cost
£0–£220
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Get an engineer to look at this
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.