Possible oven thermostat problem?

[Dazzathedrummer]

Hi,
I’ve got a Hotpoint oven that’s 9 years old. Recently using the grill caused the electricity to trip. It did this a couple of times and then the grill stopped working altogether.
The oven has two elements and the grill element works when the oven is on - so no working oven.

I ordered a new part from Hotpoint and fitted it exactly as the old one was fitted.
I switched on the oven to test and it worked fine right up to the point that the thermostat clicked off and then the electricity tripped again!

It seems the oven works fine while it’s not up to temperature but as soon as as the oven clicks off, the electricity trips.

Would this indicate that I need a new thermostat?
And if so, is it the black thing with a blue dot by the terminals at the back of the grill element?

Is it worth fixing something like this or am I likely to be fault diagnosing and replacing parts in an endless loop until I’ve basically build a new oven?

 

[Dazzathedrummer]

…just reading on here about other similar problems relating to RCD’s and other things in the circuit. We had the dishwasher running while testing the oven so turned that off and tested the oven again.
I was able to heat the oven up and have it remain on at low temperatures (60, 120, 150) but the electricity tripped after the oven clicked off at 180.
I then tried switching off all the other fuses in the RCD so only the cooker switch was on. The RCD still tripped when the oven was switched on - I’m not an expert but I’m thinking this suggests that the fault is definitely with the oven and not with something else that’s causing the RCD to be close to tripping.

 

[Alec_t]

It does sound like a thermostat problem. Perhaps its contacts arc under certain conditions?
A year ago I had to replace my oven stat (also a Hotpoint). I bought a non-branded stat with the same temperature range, similar sensor dimensions and same angular adjustment range from an Ebay store. Easy to fit and no problem since.

 

[cjcoffin]

I would suspect the grill element circuit as you say this has recently stopped working. Presumably this is the part you replaced. Was it a double element or did you replace only one half?

Often the grill element is part of a complicated circuit which heats the top oven from above with the two halves in series as well as the oven element from below.

Consequently it is difficult to diagnose oven circuit faults but it might be that the new element has got damp in storage and there is some earth leakage even though it is new.

It is odd that the fault occurs when the oven gets up to temperature and the thermostat switches it off but that does not necessarily mean the fault is with the thermostat itself. I would test all parts of the circuit for earth leakage with a multimeter before buying any more parts.