Electric Oven Temperature Problem

[Josey]

On an Indesit double oven, main oven is fine. Smaller oven was ok, but now will not reach temperature.

You can set the dial to say 220, but the oven only gets to 100. If you flick the dial back down to see where the indicator light switches off, it's always at 100, no matter how long you leave it to heat up (and of course the food is not cooking properly).

Any idea what might have failed? - I can see a thermocouple at the back of the oven, or some kind of controller?

Never taken one of these to pieces before - big job?

Thanks.

[Ian Stirling]

My first thing to do would be to make up a medium size block of ice, and place on the thermocouple.

If it's not exceeding 100C, then either the controller is turning off the heating element, or the heating element is broken. Do you own and have a license for a multimeter?

[Josey]

Tell me more, I have a meter and a dusty o-level electronics certificate :-)

Jc.

[Ian Stirling]

My first step would be to open up the oven (switch cooker isolator switch off, if you can turn it off at the consumer unit), and verify that power is off. Then, find some way of attaching the probes to indicate voltage across the oven element - you probably want the far side of the wiring loom, where it connects to the thermostat or controller board. I'd prefer not to be holding onto probes in the guts of the thing while turning it on.

Now, turn oven on, and see if the voltage stays on as it reaches 100C. If it does, then the element (or the connectors to it - check) has failed, and is going open circuit when it gets hot. If not, then it's a fault in the thermostat/...

If it's the element, then there is nothing you can do other than replace.

If it's the thermostat, then it may be repairable if it's a contact going bad, as you might be able to polish it and get it working again.

[Josey]

Ok, but I'm not sure my 20 year old certificate qualifies me to use the meter with the oven switched on.

Any other way of diagnosing the problem? I guess I could replace the thermostat and the element, but I probably won't want to do that when I see the prices.

Jc.

[Josey]

Jc.

[Ian Stirling]

Understandable.

It may be safer if you construct some wire probes for the meter. Take a core from some flex, wrap some bared wire round the probes, and then cover with insulation tape.

These can be secured round the terminals in question, before the cooker is turned on, and not touched again till it's turned off.

If it is the big oven that's died, then you can probably safely swap over the thermostats. If it's the little one, then it may not be safe - the bigger oven element may overload it.

[Owain]

"Ian Stirling" wrote | > Ok, but I'm not sure my 20 year old certificate qualifies me to | > use the meter with the oven switched on. | It may be safer if you construct some wire probes for the meter. | Take a core from some flex, wrap some bared wire round the probes, | and then cover with insulation tape. | These can be secured round the terminals in question, before the | cooker is turned on, and not touched again till it's turned off.

Slightly more safer would probably be a set of 240V-rated test leads from Maplin[1] with crocodile clip ends. Older test leads with unshrouded plugs on the meter end are rather dangerous if/when the plugs pop out of the meter.

Owain

[1] In the small display rack between the radio-control cars and the disco lighting :-)

[Peter]

Wot are you goin on about one of the elements has gone simply replace it

Peter

[Ian Stirling]

It's also possible that the fault is in the controller, though less likely.

[Josey]

Thanks for the help, didn't need to use the meter in the end, when I pulled the bottom element to take a look it was in pieces. Now I just have to find one. Merloni spares are shut for the day. Teach me not to start the job sooner.

Jc.

[Peter]

surprise suprise

Peter