The oven light comes on, the display looks fine, and the oven stays cold. Or it warms up very slowly, burns one side of the tray, or never reaches the temperature you set. Each of those points to a different part, and some are quick to work out.
Here are the usual causes, the checks you can do safely, and where the job moves from your hands to a licensed person.
How an oven heats
An electric oven has a bake element in the base and often a grill element at the top. Fan forced ovens add a third element around a fan at the back, plus the fan itself. A thermostat or temperature sensor tells the control when to switch the heat on and off. A gas oven lights a burner in the base, with an ignition system and a safety valve.
Safe checks to start with
- Check the power and safety switch If the display is dead, look at your switchboard. A tripped safety switch or breaker will cut the oven off. Reset it once. If it trips again straight away, leave it off and call a licensed electrician.
- Check the settings Many ovens have a demo or showroom mode, a child lock or a timer lock that stops the heat. Check the manual. Also make sure the clock and timer have not set the oven to a delayed start.
- Look at the elements With the oven off and cool, look at the bake and grill elements. A blister, a break or a visible gap in the metal means the element has failed. Do not touch or move the element if you are not sure.
- Check the fan Turn on the fan forced setting. You should hear the fan and feel air movement. If you hear grinding, or nothing at all, the fan motor may be failing.
- Check the door seal Close the door on a sheet of paper and try to pull it out. If it slides out easily around the edge, the seal is not holding. Look for tears, flat spots or gaps in the gasket.
- Test with an oven thermometer A cheap oven thermometer on the middle shelf shows you how far off the temperature is. Set 180 degrees and see what it reads after the oven has pre heated and cycled.
Do not open the back or side of a gas oven, and do not try to repair a gas valve, hose or ignition. Gas work must be done by a licensed gas fitter. Many electric ovens and cooktops are hardwired to the house circuit, and anything involving the fixed wiring must be done by a licensed electrician. If you smell gas, turn off the supply, open windows and call your gas supplier or emergency services.
What each symptom tends to mean
- No heat at all: a failed bake element, a tripped safety switch, a control or relay fault or a blown thermal fuse.
- Heats slowly or does not reach temperature: a weak element, a worn door seal or a faulty temperature sensor.
- Uneven cooking, with one side burning: a failed fan, a worn seal or a faulty thermostat.
- Grill works but the bake does not: usually the bake element.
- Heats too hot: a faulty thermostat or temperature sensor.
- Heats then trips the power: a damaged element leaking current, which is a safety issue.
Elements
Elements are the most common failure in an electric oven. They wear with heat and age, and they can blister if food spills onto them. Many are held by a couple of screws and a plug in connector at the back of the cavity. On many ovens an element can be swapped by a technician in one visit, once the correct part is confirmed.
Fans, thermostats and sensors
The fan moves heat around the oven so food cooks evenly. If it fails, the oven may still heat but the results will be patchy. A thermostat or sensor that reads the wrong temperature will make the oven run hot or cold. These need testing with a meter to confirm, which is why guessing often leads to the wrong part being ordered.
Door seals
A tired seal lets heat leak out around the door. The oven works harder, takes longer to heat and leaves cold spots near the door. Seals are generally a simple fit on the right model, and are worth checking before assuming a bigger fault.
Pyrolytic cleaning cycles run very hot and are hard on thermal fuses, door locks and control boards. If your oven stopped heating after a clean cycle, mention that when you call. It is a useful clue.
Cooktops
If the cooktop is the problem rather than the oven, the checks are similar. Induction cooktops need compatible cookware, and a magnet should stick to the base of the pan. Gas burners that will not light are often dirty or wet, so let them dry and clean the burner ports. Anything beyond that, especially on gas, is for a licensed person.
If the checks above do not turn up the cause, or the problem involves the fixed wiring or gas supply, get the right tradesperson to look at it. For the appliance itself, book Kobe. He repairs ovens and cooktops across Brisbane's Northside and the Redlands, and he will let you know if the job needs a licensed gas fitter or electrician instead.
Questions people ask
Why is my oven not heating but the light and display work?
The controls have power, but the heat is not getting through. A failed element, a blown thermal fuse or a faulty relay or thermostat is the likely cause. A technician can test each one to be sure.
Can I replace an oven element myself?
On some plug in models it is possible, but the oven must be fully isolated first and the correct part must be matched. If you are unsure, or the oven is hardwired, leave it to a qualified person.
Who fixes a gas oven that will not light?
Anything involving gas supply, valves or hoses must be done by a licensed gas fitter. Cleaning the burner ports and letting them dry is a safe check. If you smell gas, turn off the supply and call your gas supplier.