Smoking element on Bosch oven

[shd1970]

Can anyone help me with the following query, please?

I just turned on my Bosch hba63b150b oven onto grill setting and the element immediately started to smoke and smell
The display on the LCD was immediately a red square and from memory, whilst it is still warming up, It has like a thermostat icon in the middle which as I say was not present.
I immediately turned the oven off as the smell was bad and have unplugged it
I’ve taken the element out of the top of the oven as I was familiar how to do this having replaced it probably only 2 years ago.
The element has an inner and outer circuit as you can see by the photo I’ve attached
I’ve done a continuity test on both the inner and outer and the readings are as follows:

Outer = 39.5
Inner = 33.4

This is using a multimeter on 200 ohms setting

I’m no electrician but from a few Google searches I think the above readings suggest that the element is okay so with this in mind can anybody confirm or suggest just what the issue may be please?

It almost seemed to be that it came on at two higher heat immediately which is weird because we regularly use the grill setting on option 3 and we’ve never had an issue

We used the oven on Monday evening without any issues

Thanks in advance and hoping that I won’t be needing to buy a new oven any time soon

 

[Lower]

What did you last cook in the oven? Was it just burning off food residue?

 

[shd1970]

Thanks for the reply @Lower

So on Monday was a pastry covered pie so nothing in terms of fat to spit
Yesterday granted was Bacon on a low setting in the middle of the oven so not close enough to be able to spit and reach the elements in the top
Myself and my wife did discuss that a minute or two ago and discounted it because as I say immediately turning on the grill setting which typically takes a good few minutes to warm up properly and by that I mean about 4 to 5 minutes literally within seconds it was smoking and I mean properly smoking and quite a nasty smell too

 

[jj4091]

Did you check if there was any conduction between each terminal and the casing of the element.If there is non then it sounds like possibly a control board fault.you may be best off asking Bosch if they do a fixed price repair.

 

[shd1970]

Did you check if there was any conduction between each terminal and the casing of the element.If there is non then it sounds like possibly a control board fault.you may be best off asking Bosch if they do a fixed price repair.

Thanks for the reply @jj4091

Apologies, but could you explain how I would do that, please?
As soon as the issue happened as I say because of the smell I disconnected and took the back off the oven and remove the element as I recall replacing this a few years ago however I can’t remember what the symptoms were
As you see, I’ve checked the resistance on both the outer and the inner elements and the readings were as follows :

200 ohms setting

Outer 39.6
Inner 33.5

 

[shd1970]

@flameport - is this something you could help and advise on please flameport as I just saw one of your YouTube clips for testing elements

Sorry for looping you in directly

 

[jj4091]

Test the resistance using your multimeter from each terminal to the body of the element not just between the terminals.You should measure an open circuit. IE zero ohms. Using a multi meter is not actually a guarantee it is not shorting to earth as you would need a proper resistance tester to be certain. But if the oven is protected by an RCD at the consumer unit that would normally trip with a short to earth so just thought I would ask as you don't mention the supply to the oven. As I said, from your discription of the problem it seems unlikely to be a faulty element.

 

[Harry Bloomfield]

I just turned on my Bosch hba63b150b oven onto grill setting and the element immediately started to smoke and smell

It is most probably, just food or fat, which has made it's way onto that grill element. Just run it to burn off the residue.

Is the oven circuit fed via an RCD, or a RCBO?

 

[Harry Bloomfield]

Test the resistance using your multimeter from each terminal to the body of the element not just between the terminals.You should measure an open circuit. IE zero ohms.

NO! Not zero Ohms, it should read high/maximum/infinity...

 

[jj4091]

NO! Not zero Ohms, it should read high/maximum/infinity...

Yes sorry should have said "no reading"

It is most probably, just food or fat, which has made it's way onto that grill element. Just run it to burn off the residue.

Is the oven circuit fed via an RCD, or a RCBO?

The problem with the LCD suggests it is something else to me.

 

[shd1970]

Test the resistance using your multimeter from each terminal to the body of the element not just between the terminals.You should measure an open circuit. IE zero ohms. Using a multi meter is not actually a guarantee it is not shorting to earth as you would need a proper resistance tester to be certain. But if the oven is protected by an RCD at the consumer unit that would normally trip with a short to earth so just thought I would ask as you don't mention the supply to the oven. As I said, from your discription of the problem it seems unlikely to be a faulty element.

So yes, I’ve just tested both elements for resistance with a probe on the connector and the other probe on the actual body of that element and you’re correct it shows an open circuit and they are both the same
When the incident happened, it didn’t trip my RCD
Do you think this could be a thermostat issue which from what I’m seeing is actually what they call an oven temperature PTC sensor ?

I’ve got the lid off, so I’m gonna do a test on that shortly also

Thanks again for your support and input @jj4091

 

[shd1970]

It is most probably, just food or fat, which has made it's way onto that grill element. Just run it to burn off the residue.

Is the oven circuit fed via an RCD, or a RCBO?

@Harry Bloomfield - it’s on the circuit specific for my kitchen sockets which on the consumer board just has a trip which with no test buttons which I believe means it’s an RCD

 

[shd1970]

NO! Not zero Ohms, it should read high/maximum/infinity...

 

[shd1970]

A bit more info
I’ve just done a resistance test on the PTC sensor
At room temperature the reading was 533 on a setting of 2000 ohms but then if I held the sensor and breathed on it, it actually went up to 546

However, I’m close inspection if you look on my photo it actually looks like the white almost chalky type wick is actually split in two places

Considering that my cooker when you use the grill, which is what we was doing, which uses the top element you have three options temperature 1, 2 or 3, but that is simply done by turning a knob so would the temperature sensor be involved or does it regulate the heat some other way?

 

[Harry Bloomfield]

@Harry Bloomfield - it’s on the circuit specific for my kitchen sockets which on the consumer board just has a trip which with no test buttons which I believe means it’s an RCD

An RCD, or RCBO, will have a test button. If there is no test button, it will be an MCB.