Oven won't heat, heats unevenly, or won't hold temperature

Most of the time an oven that won't heat comes down to one of two things: a heating element has burned through, or the temperature control has failed — the thermostat or the NTC sensor. Complex electronics are rarely to blame. If the light is on, the fan spins, the display shows the set degrees, but the dish stays cold or bakes poorly, that symptom has a very specific source, and you can narrow it down before the oven is ever taken apart.

This article is only about electric ovens — built-in ones and the oven section of a freestanding range. Gas ovens are out of scope here and we don't repair them: they run an entirely different gas-safety logic with burners, a thermocouple, and ignition.

Below, symptom by symptom: which part is responsible, what you can check yourself, and where the service work begins.

No heat at all — which element and the power supply

A typical built-in oven has several heating elements: the lower one (for the main bake), the upper one with the grill coil, and — in fan ovens — the ring element around the fan at the back. Each can burn out on its own. That's exactly why an oven so often "won't heat" when in reality it only fails to heat in one mode.

The first thing to ask yourself: does it fail in every mode, or only one?

• Cold in every mode, display and light working → most likely the supply to the elements or the control relay, less often several elements at once.
• Cold in every mode, display also dark, other kitchen sockets dead too → look for a fuse or breaker in the distribution board, not the oven.
• Heats only on the bottom or only on the grill, but not in the other mode → that specific element or its contact has failed.

A heating element burns "open" — the coil inside snaps and the circuit breaks. Often you can see it with the naked eye: a swelling, crack, or scorched patch on the element, sometimes a blister in the metal sheath. In older Riga apartment blocks the voltage dip at switch-on adds extra strain to an already tired element, and it's during the busy cooking season, when the oven runs often, that this finishes it off.

On the supply side the usual culprits are oxidised or burned contacts at the element terminals, plus a control relay on the board that no longer closes the circuit. This is checked on the bench with continuity testing and voltage measurement under load. That isn't a DIY job: the elements sit on 230 V mains, and the oven has to be disconnected from power to be opened up.

The DIY boundary here: you can check the breaker in the distribution board, try another mode, and visually inspect the element you can see inside the cavity. Removing the element, continuity testing and replacing it, diagnosing the relay — that's already service work.

Heats unevenly or won't brown — the fan and element balance

When the oven heats but the bake burns on one side and stays pale on the other, or dough rises unevenly, the issue is usually heat distribution, not the oven being "broken" outright.

In a fan oven (hot air / convection) the rear fan drives air around the cavity, and it has its own ring element around it. If that rear element has burned out while the lower one still works, you still feel heat and the oven reads as heating — but the air no longer warms evenly and baking "drags on." The reverse case: the element is fine but the fan motor won't spin — the warm air doesn't distribute, and heat concentrates under the top or above the bottom element.

A table to separate the symptoms:

It's important not to confuse uneven baking with wrong temperature. The first is about how heat spreads through the cavity; the second about how hot the cavity gets. In practice you tell them apart with an oven thermometer: place it in the centre and compare with the setting. If the centre matches but the edges differ sharply, that's a distribution issue — elements or fan.

Won't hold the set temperature — thermostat / sensor

If the oven heats up but then "floats" — too hot one moment, too cold the next — or always bakes at a noticeably different temperature than set, the temperature control is at fault. In modern electronic ovens this is measured by an NTC sensor: its resistance changes with temperature, and the board switches the elements on and off from that signal. Older, simpler ovens use a mechanical thermostat with a capillary.

Typical symptoms and what they mean:

• The oven runs much hotter than set (the bake burns even on a low setting) → the sensor "lies" low, so the board keeps the elements on too long, or the thermostat contacts are stuck closed.
• The oven runs much cooler than set (never bakes through) → the sensor reads high, the board cuts the elements early, or the thermostat opens too soon.
• The temperature visibly swings — the light/display shows the oven heating and cooling across a wide range → NTC drift or a weak contact in the sensor circuit.
• The oven switches itself off after a while → the thermal fuse (overheat protection) may have tripped, and that's often triggered by blocked cooling or an already-faulty sensor that stops the board cutting the element in time.

The NTC sensor is checked by measuring its resistance cold and warm and comparing it to spec — a typical bench task. A mechanical thermostat is checked by the state of the capillary and the behaviour of the contacts. In both cases the part is a small one against the whole oven, and a replacement restores accurate temperature. The thermal fuse is never replaced "blind" — you first have to find why it tripped, or it will blow again.

The DIY boundary: at home you can only confirm the symptom with an oven thermometer and note how many degrees the oven is off by — that greatly speeds up diagnostics. Measuring and replacing the sensor or thermostat is service work.

Fan noise or air not circulating

In a fan oven the rear motor turns an impeller that drives hot air around the cavity. When this assembly nears the end, you hear it and feel it.

• Growing hum, rumble, or a metallic rubbing noise while running → the fan motor bearing is worn. It often gets worse during the heating season: in dry, hot air the old grease in the bearing dries out faster.
• Rattle or scraping → something is touching the impeller: a bent blade, a loose element bracket, or baking residue.
• The fan is silent but the oven heats unevenly → the motor isn't turning at all (winding, capacitor, or supply to the motor), and the mode is no longer a true "fan" mode.
• A separate noise after the oven switches off → that's usually the cooling fan (tangential), which cools the fascia and electronics, and is meant to run on for a while after cooking. If it's noisy or stops too early, the board can overheat and the protection trips.

There's practically no DIY here: to reach the cavity fan you have to remove the back panel with the oven disconnected, and the cooling fan is hidden in the housing. Both the motor replacement and the impeller cleaning we do at the service centre.

Door, seal and light — small things, but common

Not every problem sits in the electronics. A large share of "bakes badly" complaints end at the door.

A heat-resistant door seal (usually a woven fibreglass cord) runs around the cavity. When it hardens, cracks, or comes away at the corners, hot air is pushed out, the oven can't hold temperature in the upper part, and the bake won't brown. The tell: the door or the panel above it runs noticeably hotter than before, and you feel a draught of hot air around the door. You can inspect the seal yourself — on models that allow it, you can often pull it out and refit it without tools.

Door hinges and mechanism: if the door no longer closes fully tight or "sags," worn spring hinges are to blame. That's a mechanical part, and a door that isn't fully closed makes all the rest of the diagnosis misleading — this has to be sorted first.

Oven lamp: an unlit cavity is not a sign of a heating fault. Replacing the lamp is a typical DIY job: disconnect the oven from power, unscrew the glass cover, and fit a new high-temperature lamp of the correct type. If a new lamp still won't light, the fault is in the holder or wiring — then it's service work.

Before hauling the oven in, it's worth a simple reset: switch the breaker in the distribution board off for a couple of minutes and back on. Sometimes that clears an accidental control "freeze." If the problem comes back, the reset doesn't hide it — that already points to a real fault.

Repair or replace a built-in oven — decision table

A built-in oven sits in a niche against the kitchen units and is often matched to the hob and the fascia — so replacing it is not just a matter of buying a new appliance, but also a question of whether a new oven fits the niche and whether the link to the hob controls is compatible. That shifts the repair-or-replace calculation compared with freestanding appliances.

A general framework (we identify the fault on-site):

A built-in oven's typical active life is around 4–6 years before the first more serious component repairs, and well looked after it lasts considerably longer. The core principle: one clearly localised part (element, sensor, seal, motor) is almost always worth repairing; several expensive parts failing at once on an old oven is the moment to think about replacement. We explain this logic more fully in the article on when to repair or replace an appliance, and a neighbouring topic is the induction hob that won't heat, because a built-in hob is often the other half of this same problem.

This is exactly why on-site diagnostics is the decision point: the technician looks at which part has failed, and only then is there any point talking about the scope of the repair and whether it's worth it. More on what we do is on the home appliance repair page.