Backersafe Anticorrosive immersion

[Joshel]

I've recently fitted a replacement economy 7 fortic combi cylinder
But the backersafe immersions work for a week or so and then keep tripping.
I've replaced the immersions and a sparky has checked electrics but the same thing keeps happening. I've adjusted the stat & pressed reset which works but then same scenario again. Anyone have any ideas?

 

[seasickstevie]

Is the element in the side of the cylinder (as opposed to the top)?
Some elements have two tubes that take the stat. The idea is that you put the stat in the lowest/bottom tube. That way the water that's immediately heated, rises away from the stat.
Just a thought, but maybe it's been put in the higher tube.