Overheating immersion

[Huge]

A couple of months ago, the immersion heater overheated and melted both the insulation and its plastic cap...

So I assumed the thermostat was faulty, bought and fitted a new one and fabricated a new cap from plastic drainpipe.

The new thermostat has an overtemperature trip, which keeps tripping. So, whatever's wrong is still wrong. I carefully remade all the joints when I replaced the thermostat (I assumed that's what the problem was), so I imagine it can't be that.

Could the element be furred up? We have very hard water and our water softener packed up years ago....

[tony sayer]

In article , Huge writes

Why ever not change the whole thing?. They aren't expensive and chances are that if its been that hot, its not done the element a power of good as they don't last that long and the improvised cover, sounds well improvised;).

Bet that theres a partial short from live to earth in the heating element, so part of the heater is going much hotter than it should. Shorts in immersion heaters are a regular source of RCD trips.....

[James Salisbury]

The element could well be furred up, and if it is at the bottom of the cylinder there could be a few buckets of scale wating to be shifted!! Try here

[Huge]

Because getting them out is non-trivial when they've been there for 20 years.