On Sun, 17 Jan 2016 22:23:04 -0000, "Ian Field"
wrote:


The last element came out surprisingly easily - so I'm remaining optimistic.

What size was it back then?.. :-)

I have a 27 inch element fitted at the top of a 42 inch cylinder.
Water heating is normally by the CH coil but I occasionally test the
immersion heater to make sure it works.

The manufacture's leaflet states:-
"... this heater will only effectively heat water ABOVE, it is
important that the correct length be fitted, i.e. if an 18" heater is
used in a 36" cylinder only 45-50% of the water will be heated"

I have sensors at the top, 2/3 and 1/3 levels and a typical immersion
heater test over a few hours shows that the tank is not fully heated.
https://dl.dropboxusercontent.com/u/.../DECimmhtr.pdf