Why your oven isn't heating up (and how to fix it yourself this weekend)

It's 5:30 PM on a Saturday. The lamb is seasoned, the potatoes are parboiled, and the oven is sitting at 30 degrees. It has been preheating for 40 minutes. You are staring at a very expensive metal box that refuses to do the one thing you bought it for.

By the end of this guide, you will know exactly what has failed, what you can safely check yourself, and when you need to step back and call a professional.

Electric oven not heating up: the usual suspects

Electric ovens are simple machines. When an electric oven is not heating up, look at the power supply, the element, or the thermostat.

First, check the basics. Did the circuit breaker trip? We see this constantly in older Sydney homes where the kitchen and laundry share a circuit. If the oven is dead entirely with no display, knowing how to check if a power point is safe or checking the switchboard is your first step.

If the display works, check the heating element. It works.

Then comes the bake element. Most electric ovens have two — one at the top for grilling, one at the bottom for baking. The bottom one does 90% of the heavy lifting. It is a steel tube filled with resistance wire, and over years of heating and cooling, the metal fatigues.

We look after a client in Strathfield, a post-war double-brick, whose oven died the morning they were hosting a 40th. The bake element had blistered and snapped clean through the casing, tripping the safety switch whenever they turned it on. A repair like that costs about $180 to $280 plus GST for the part and labour, assuming the element is still available for your model.

If the element looks intact, test it. Set your multimeter to ohms. Touch the probes to the element terminals. A functioning element reads between 20 and 40 ohms. If it reads open or infinite resistance, the wire inside is broken.

When your oven is not heating but the fan works

This is the classic symptom. The fan kicks in, the internal light is on, the display says it is 200 degrees, but everything is cold. When your oven is not heating but the fan works, the control board is getting power and telling the system to run. The heating component is what failed.

In this specific scenario, the problem is entirely isolated to the heating circuit. That means either the element is broken, the thermal fuse has blown, or the relay on the control board has failed closed. They behave identically from the user's perspective.

Honest advice here: if you have confirmed the element is intact with a multimeter, stop. Diagnosing a failed control board relay requires pulling the appliance away from the wall, removing the back panel, and energising the unit to trace the voltage drop. It is not a weekend DIY job. If a tradie refuses to quote a fixed price for a control board replacement because they "need to see it first", they probably do not know what they are doing. It is a standard diagnostic process.

Gas oven not heating up: the igniter problem

Gas ovens fail differently. They have a thermocouple or a flame sensor that determines if the gas valve can open. If the gas oven is not heating up, the igniter is almost always the problem.

Modern gas ovens use a "glow bar" igniter. It draws electrical current, heats up to a bright orange, and that draw physically opens the gas safety valve. The valve will not open until the igniter pulls a specific current, usually around 3.2 amps.

The tricky part? The igniter can still glow bright orange but be too weak to pull the required amperage. It looks perfectly functional. It just is not opening the gas valve. We've never gotten a straight answer from the manufacturers on why a component can glow perfectly but still fail to open the valve. It seems like a design flaw, but we just replace the part.

How do you know if your gas oven igniter is broken? You will hear the click of the gas valve trying to open, but nothing happens. Or you will smell a faint whiff of gas that dissipates quickly. Do not force it. Do not try to light a gas oven with a match if the igniter is failing. The gas builds up before the flame catches, and you will singe your eyebrows.

How to fix an oven that won't heat: DIY checks

Here is what you can safely do before calling a technician:

1. Check the breaker. Find your switchboard. Look for a tripped oven or kitchen circuit. Reset it once. If it trips again immediately, you have a dead short. Stop.
2. Inspect the bake element. Open the door. Look at the bottom. Are there blisters, cracks, or a clean break? That is your answer. Order the replacement part using your oven's model number (usually on a sticker inside the door frame).
3. Check the clock and timer. This sounds absurd, but we have been called to homes where the oven was simply set to "Sabbath mode" or the timer had paused the start function. Consult your manual. It happens more than anyone admits.
4. Listen to the gas igniter. Does it click? Does it glow? If it glows for two minutes and shuts off without lighting, the igniter is weak.

That is it. Anything beyond these checks involves taking panels off the oven and testing live 240-volt circuits.

If you messing with the internal wiring of an oven, you are dealing with a 240-volt appliance that pulls significant current. A wiring mistake inside an oven can start a fire behind the wall. We see dodgy DIY wiring jobs in older homes across Sydney, often done by previous owners, and it is never worth the few hundred dollars saved.

The Wenest take

In the homes we work in, the version of this that actually goes wrong is sourcing the part. A homeowner correctly diagnoses a blown element, orders a replacement online, waits two weeks for delivery, and the replacement is slightly wrong. The plugs do not match. Or the wattage is incorrect, which will eventually burn out the thermostat. The fix is getting the diagnostic right, but getting the exact OEM part number right.

If getting the part wrong sounds like a massive headache you don't need, don't do it yourself. We coordinate appliance repairs for our members across Sydney. We have the right tradie for the job handle the diagnostics, source the correct part, and fit it safely. See how Wenest works.

This article is general guidance only. Any electrical or gas work in NSW must be performed by a licensed tradesperson — see NSW Fair Trading for licence verification.