Washing machine works fine on temperatures up to 75, but on 90 there is a problem. Works fine for about 40 minutes, and heats up the water, but then trips out (still on Wash cycle). Leaving a few minutes and then re-connecting supply works – machine continues through Wash cycle and on to the end.
I suspect a faulty heater, but why does it only trip on 90 and after about 40 minutes – I would have expected problems at other settings too or sooner.
There is electricity running through the heater – it works fine for a time and heats the water very well. It is only after about 40 minutes on the hottest setting that the supply is tripped. Presumably, that is when the hottest temperature is actually reached.
Is it possible for an element to function properly most of the time, and only trip when it reaches a particular high temperature?
My colleague refers for the need for you to check the “continuity” of the element. That involves using a test meter (preferably an insulation tester) to establish the full electrical state of it. A necessary test we in the trade always perform as a matter of course. 😀
The hotter the element gets the more it will “Flex” if the wire inside the element moves enough to touch the Earthed outer sheath then your RCD will trip out. The only way to find the Fault is either use a Megger on the element to check Insulation when it’s hot or by replacement.