Lamona HJA4620 Oven tripping circuit

[ChumaO]

Hi, first post here ...
I have a Lamona HJA4620 oven that keeps tripping the circuit when I try using the main oven. The oven is hard-wired to a dedicated circuit. The top oven works well but the main bigger oven trips the circuit after about 5-10 mins heating.
Initially, I thought the problem was the main oven top element which I replaced but it is still tripping.
I have been trying to see which of the components is causing the problem by:
1. isolated the top element by disconnecting the power source to the element
2. isolated fan element
3. isolated both the fan element and top element
In all the above cases I still have the oven trip the circuit after about 5-10mins heating and when I try changing the setting using the function selector.
I am now suspecting the function selector or the thermostat - heating control?
Has anyone any advice on what could be the problem or what next I could do in my troubleshooting to know which component to change.
Many thanks for your help.

 

[telectrix]

is there a bottom element? your symptoms point to an element failing as it gets hot and expands.

 

[ChumaO]

is there a bottom element? your symptoms point to an element failing as it gets hot and expands.

Yes, there is a bottom element. I have not tried isolating that. Will probably do that. Would that be where the problem is?

 

[telectrix]

could be. only way to find for certain is to IR test the elements ( what we used to call meggering) shoving 500V D.C. up 'em, see what the fault is.

 

[littlespark]

You say “tripping the circuit”
Are we talking a circuit breaker or an rcd/rcbo? (The ones with the little test buttons)

ive seen “faults” that were down to the cumulative effect across all circuits on a split board. Nothing wrong individually, but together caused the main rcd to trip.
Came down to 2 double sockets with usb chargers built in, fitted by the homeowner.

 

[ChumaO]

You say “tripping the circuit”
Are we talking a circuit breaker or an rcd/rcbo? (The ones with the little test buttons)

ive seen “faults” that were down to the cumulative effect across all circuits on a split board. Nothing wrong individually, but together caused the main rcd to trip.
Came down to 2 double sockets with usb chargers built in, fitted by the homeowner.

Thanks. It may well be faults from cumulative effects. However, my isolation test seems to be pointing to the base (bottom) element. I have isolated this and the oven seems to be heating OK with the other elements and no tripping so far. I'll keep an eye on it whilst waiting for the new element to arrive.
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You say “tripping the circuit”
Are we talking a circuit breaker or an rcd/rcbo? (The ones with the little test buttons)

ive seen “faults” that were down to the cumulative effect across all circuits on a split board. Nothing wrong individually, but together caused the main rcd to trip.
Came down to 2 double sockets with usb chargers built in, fitted by the homeowner.

It is the one with test buttons - RCD

 

[telectrix]

bear in mind that with 1 element dissed, the thermostat will not cut off correctly as the heating will not be even, top to bottom. your chicken will burn on the top and be cold underneath.

 

[ChumaO]

bear in mind that with 1 element dissed, the thermostat will not cut off correctly as the heating will not be even, top to bottom. your chicken will burn on the top and be cold underneath.

Noted. And thank you