What makes an oven heat unevenly?
A conventional oven heats from elements at the top and bottom, so some difference between shelves is normal. A fan oven uses a fan and a ring element at the back to move hot air around evenly. When food burns on one side or on one shelf only, part of that system is not doing its job.
Common causes
These are the usual causes, starting with the ones you can check yourself.
At a glance
| Cause | Who fixes it |
|---|---|
| Shelf position and trays | You can check this |
| A worn or loose door seal | You can check this |
| The fan motor is slow or has stopped | Technician |
| An element has partly burnt out | Technician |
| The temperature sensor or thermostat is faulty | Technician |
- 1
Shelf position and trays
You can check thisA tray that is too large blocks the air from moving around, and food placed close to an element cooks faster. Leave a gap of a few centimetres around trays and use the middle shelf for a single tray.
- 2
A worn or loose door seal
You can check thisHeat escapes through a torn or flattened seal, so the area near the door runs cooler. You may feel heat on the front of the oven or see marks on the glass around the edge.
- 3
The fan motor is slow or has stopped
TechnicianOn a fan oven, a failing fan motor stops the hot air moving around. The oven still heats, but the back gets hot while the front stays cool. A noisy, grinding or silent fan points here.
- 4
An element has partly burnt out
TechnicianAn element can fail along part of its length or stop working completely while the other elements carry on. If only the top or only the bottom of the food cooks, one element is likely faulty.
- 5
The temperature sensor or thermostat is faulty
TechnicianA sensor that reads wrong makes the oven cycle the elements at the wrong times, so the temperature swings up and down instead of staying steady.
What you can safely check yourself
- Check the traysUse one tray on the middle shelf with space around it and see if the result improves.
- Check the door sealWith the oven cold, look around the seal for tears, gaps or flat spots. Close the door on a sheet of paper: it should hold firmly all the way round.
- Watch the fanOn a fan oven set to a fan function, look through the glass. The fan should turn smoothly without grinding.
- Look at the elementsWith the oven switched off at the wall and cold, look for blistered, split or sagging elements.
When to stop and call a technician
The fan grinds or does not turn, an element is split or blistered, the oven trips the power, or the food still cooks unevenly after these checks. Switch the oven off at the isolator before any panel is removed. Elements and the fan sit behind panels that only a technician should open.
Still having trouble with your oven?
Our technician comes to your home, usually the same day. The R450 call-out falls away if you go ahead, and you get a fixed price in writing before any work starts.
How a technician diagnoses it
- Function checkThe technician runs each oven function to see which elements and the fan are working.
- Element testEach element is tested for continuity and insulation.
- Fan and sensor testThe fan motor and temperature sensor or thermostat are tested against the oven temperature.
- Fixed priceYou get a fixed price in writing before any part is replaced.
Is it worth repairing?
Usually worth repairing when
- The fault is one element, the fan motor or a door seal
- The oven is a built-in model
- The cavity, door and controls are in good condition
Consider replacing when
- The control board and several elements have failed together
- The cavity is badly rusted
- Parts for the model are no longer available