wiring is exactly as the bottom immersion, which is working fine now, we have hot water YAyy. multimeter on AC, it measures 8.4v, i measured first at immersion, then at switch, then at wires to switch from wall, all are reading 8v.
This is where i am stomped, because im not an electrician i dont know where to check.
the heater timer control on the kitchen wall shows a light when boost is pressed and when pressed the multimeter shows a AC measurement, when off it does not, as i expect. The same fuse in the fuse box controls both immersions on the tank so i presume its not that. im thinking there must be a problem from the wiring supplying the tank. how to trace this is another matter.
I presume due to the green corrosion on the one replaced that it has not worked in a good while.