Oven not heating: what to check before you call anyone

Why "not heating" is usually not a fault

Bosch answer the search "oven not heating" on their website by naming the heating element and telling you to book a repair. Their own instruction manuals give three free causes the website leaves out: the oven is in demonstration mode, the clock has not been set, or the door is not closed. That gap between what a manufacturer publishes for the public and what it prints in the manual is how a repair visit to a cold oven ends with the engineer pressing a button. Before you book anything, spend ten minutes on the checks below, in this order. They are all things a householder can do from the front of the appliance.

The checks, in order

1. The cooker switch. The separate wall switch that feeds the cooker circuit gets knocked off by a kettle, a cleaner or a child more often than anyone admits. It is usually above the worktop, to one side of the hob, and it may have a neon that is off. If your oven has a display that is dark, this is where to look first; if the display is lit, the switch is on and you can move on.

2. The consumer unit. If the display is dark and the switch is on, check whether the breaker or RCD for the cooker circuit has tripped. AEG include this in their own remedy for F102. Reset it once. If it trips again when the oven is switched on, stop: that is a supply or appliance fault that needs an engineer, and repeated resetting of a breaker that is doing its job is not a fix.

3. Demo mode. A lit oven that accepts every setting and never warms is the classic sign. AEG say it can switch itself on after a power cut, and their exit code is 2 4 6 8 through Basic Settings and Service. Hotpoint's tell is the word DEMO appearing every sixty seconds. Bosch manuals describe a d or an o in the temperature display. If you see any of these, nothing is wrong with the oven.

4. The clock. Hotpoint treat a flashing clock as an interlock, not a cosmetic state: until the time of day is set, the oven will not cook. Bosch and Neff ovens behave the same way after an interruption. Set the time; on a Hotpoint showing a flashing 12:00, touching the clock key confirms it. If the clock keeps clearing itself, something is interrupting the supply, and that is a wiring question rather than an oven one.

5. A lock. SAFE, Loc, a key symbol or a padlock means the controls are locked, or the door is. AEG's child lock clears by turning the function knob to off and holding the two lock buttons for three seconds. A padlock after a cleaning cycle releases when the cavity cools and must not be forced. Hotpoint's key lock is in settings.

6. The door. Close it firmly enough to feel it seat on the catch rather than resting against the seal. A door microswitch that is not made stops the heating on many models; AEG name the door lock as one of two causes for F102.

7. The programme. An oven left in a timed or automatic mode waits for its start time and heats nothing. Check that nothing is set to delay the start.

8. The probe. On a Hotpoint showing F3E3 the food probe is not making proper contact. Let the cavity cool, unplug the probe and refit it firmly — do not reach into a hot oven for a connector, the code is not urgent enough to be worth a burn.

Narrowing a real fault: the grill test

If all of that is in order and the oven is still cold, one test tells you a great deal. Run the grill by itself. A grill that glows while the fan oven stays cold points at the fan oven element specifically, which is a cheap part and the commonest repair in this category. A grill that also stays cold, with a lit display, points higher up: a thermostat, a relay on the control board, or the supply to the heating side of the appliance. Either way, note the result, because it is exactly what the engineer wants to hear on the phone and it shortens the visit.

A second useful observation is what happens when the oven does try to heat. A fan that runs with no warmth is different from silence. An oven that heats briefly and cuts out is different again, and can be the cooling fan rather than the element: Miele's F60 reports insufficient ventilation, and their first published check is that the air duct above or below the door is not covered or blocked by a trim or a filler panel added during a kitchen refit.

Where to stop

This is the point at which the honest line runs. The element sits behind the rear baffle plate inside the cavity, and it is tempting to take four screws out and look. Do not. Bosch advise against owner repair here, and the reason is not the element itself but what it is connected to: a cooker circuit that you cannot isolate by pulling a plug, because there is not one. The oven's element and its wiring are at mains voltage, the cavity walls carry baked-on fat, and a loose connection you did not notice is how a repair becomes a fire. Anything past the checks above — the element, the thermostat, the fan, the door lock mechanism, the control board — is work for a qualified appliance engineer, who will isolate at the cooker switch and the consumer unit before opening anything.

Two situations need a different trade. If the display shows Neff Er2, or any message about the mains connection, the fault is in the fixed wiring of your kitchen rather than in the oven, and Neff's instruction is to switch off the fuse in the fuse box and have the appliance connected correctly by an electrician. The same goes for an oven that was fitted recently and has never heated properly: that points at the installation, the connection is fixed wiring that has to meet BS 7671, and whoever fitted it should normally be putting it right at their cost.

What it costs

The figures below are the ranges the code pages on this site carry for the codes involved, and they are brackets rather than quotes.

• Nothing at all if it turns out to be the wall switch, demo mode, the clock, a lock or the door. Every one of those is a cause the manufacturers publish, which is why the checks above come first.
• A fan oven element is typically £20 to £50 as a part, and a repair visit with the element fitted usually lands between £100 and £200. Most of that is the visit, not the part.
• A door lock on an AEG F102 is £35 to £70 for the part plus the call-out.
• A cooling fan, the likely outcome on a Miele F60 that returns with a clear duct, means a part plus a visit, and the code page brackets it up to about £220.
• A control board on a mid-range oven can approach the value of the appliance, and on Miele F134 the range runs to about £300 before you know whether it is the sensor or the control that has failed. Get it diagnosed before authorising the part.
• An electrician's visit to inspect and correct a cooker circuit connection is typically £80 to £250 depending on what is found. It is not an appliance repair and is unlikely to be covered by an oven warranty.

If the oven is more than about eight years old and the diagnosis is a control board, ask for the price of the part before agreeing to the repair. Manufacturers differ on how long they hold electronics for, and a board that is no longer available ends the conversation.

What to tell the engineer

Say which checks you have done, whether the grill works, what the display shows and exactly how it is written, and the model number from the rating plate, which on a built-in oven is normally visible with the door open rather than on the back. If the oven shows a code rather than simply staying cold, the page for that code on this site carries its published meaning and whether a reset is worth trying: How to reset an oven covers the resets by brand.

Sources

• Bosch UK, Home Connect support: "Oven not heating"; Bosch built-in oven instruction manuals, "Malfunctions" chapter.
• AEG UK support: F102, Demo mode and SAFE articles, retrieved August 2026.
• Hotpoint UK support: clock flashing, DEMO mode, F3E3 food probe.
• Miele UK: F60 insufficient ventilation, F134 cavity temperature; Miele operating instructions for H-series ovens.
• Neff UK and Siemens UK troubleshooting database: Er2, wrong mains connection.
• Cost brackets are those published on the code pages for AEG F102, Bosch "Not heating", Miele F60 and F134, and Neff Er2, each with its own sourcing.
• Building Regulations Approved Document P (England) and the Welsh Government equivalent, on notifiable electrical work in kitchens.