The immersion heater in my house is of a type I haven't seen anywhere else. There are no elements in the main tank. Instead the element is mounted inside a small vertical cylinder plumbed into the side if the tank but seperate from the main tank. Its mounted vertically with the element upside down and fitted from the bottom (which makes it hard to see the stat setting without a mirror). The secondary cylinder is 3 inches diameter and about 15 inches long.
A while back I noticed that running the immersion even for a short time produced dangerously hot water. Ther was also a bubbling noise from the cylinder when the immersion was on.
So I replaced the stat (7") set it for 60 and thought that would be that. Same problem.
Any ideas....
Peter Hawkins