Yup exactly what I thought…this is the sequence of events which would have occurred…in order.
- You removed the circlip and the vacuum breaker plunger and seal dropped into the boiler
- You didn’t realise the ramifications when the machine turned on and you were not there
- The kitchen filled with steam as did the inside of the machine and water condensed everywhere, all coming out of that hole..
- then 5 and 6 happened which fried your heating element
- periodically the pump refilled the steam boiler but unluckily for you the boiler did not cut out when the machine saw low water (which I believe it did in those days) and for some reason the heating element didn’t turn off when the autofill probe tip was exposed.
- With no pressure in the boiler the temperature could not get above 100C, the limit stat is set to about 135C and unluckily even though there was lots of steam, nothing in the case tripped out
- or more likely the following happened as 2 faults at the same time in point 5 are very unlikely
- the steam eventually fused out the Gicar box, limit stat, pressure stat, or damaged one of the SSRs.. I don’t know which….and the heating elements are probably OK
The last point is probably what happened as more than 1 thing would have to not work
This bit is important, was it a breaker or an RCD that tripped, the first trips on overcurrent, the second on a short to earth at 30 mA, If it was a big overcurrent it’s more likely a direct short which would often be visible…or the boiling on the heating element was so fierce that the steam prevented the autofill probe from cutting power to the element and the bubbling caused parts of the element to get exposed and it was old so simply gave out.
Below is what dropped into your boiler when you removed the circlip, you can actually replace the sealing O ring on these for a few pence.
Here is what a MK2 should look like inside, you can see the limit stat on the side of the boiler on the second photo
Next steps in diagnosis:
- Remove the spade connectors to the heating element so it can’t turn on…is it still tripping out
If it is, then it will be the heating element, remove and inspect it. also, retrieve lower part of vacuum breaker and inspect boiler for scale.