On 28/05/2019 16:58, Chris Hogg wrote:
On Tue, 28 May 2019 16:30:39 +0100, John Rumm
wrote:

On 28/05/2019 15:38, JoeJoe wrote:
On 28/05/2019 15:24, Chris Hogg wrote:
On Tue, 28 May 2019 15:04:51 +0100, JoeJoe wrote:

Have had one of these

http://tinypic.com/r/dnf4le/9Â*Â* (10.8Kw)

for the last 10+ years, used daily.

3 years ago or so the water temperature started to play up (would turn
cold suddenly when in use), and at the advice received here I cleaned
the filter on the water inlet, which fixed it, and no problems since.

Yesterday it started to misbehave again: under Medium or Low setting the
water is completely cold. When set to High it almost reaches acceptable
temperature when the dial is on max, but not hot enough. Anything below
that is pretty much cold.
Usual setting for this time of year is around 1, perhaps 2 o'clock.

I tried to clean the (very dirty) filter again, but it had no effect.

Any idea what to try next please?

How many elements in the heater tank does it have? Having three
settings suggests three. It sounds as if at least one, and possibly
two, have failed in some way, either gone O/C or the switches have
failed.


But even when it is set to High the water is only lukewarm when the dial
is set to max...Â* So two elements are completely dead and one "half dead"?

It might have two elements - switched in parallel, with one being more
powerful than the other. So it can switch low power element, high power
element, or both to give the three settings.

If you have a multimeter, its easy enough to test. Isolate the power,
and take the cover off. Look for the wires connecting to the small
boiler can. I am guessing there will be probably be 4 - a neutral, an
earth, and two switched lives.

If unsure, post a photo where we can see it.

If you measure the resistance across the element between neutral and the
first switched live, then the second. You may well find your problem
there. If not it could be the switching has (partially) failed. The one
you picture looks like it might have electronic switching - that can
make it harder to test when powered down, but you might be able to swap
the switched lives to the boiler and then reassemble and test to see if
the fault behaviour changes.


https://tinyurl.com/y3mnx2sr


mine, I believe, is the J95D - the newer model (this one is the J92)