Have one of these in the spare shower room (installed 5 years ago, so
perhaps our's an older model, but look identical as far as I can tell).
Rarely used, but recently started to misbehave. It has 3 water pressure
button (low/medium/high), and then a dial to set the temperature. We
have always had it used on the High setting, and the temperature dial at
around the middle setting.
Now in the High setting the water temperature is far too hot (even with
the dial set to minimum). In the Medium setting the temperature is too
low (even with the dial set to maximum)...
I assume something to do with a thermostat? Is it worth preparing?
Considering its working environment my top priority is safety of course...
You could check the filter. There's sometimes a little mesh filter, probably on the inlet.
A common problem is scaling. If you think of how scaled up your 2 or 3 kW kettle gets in a year, then consider the shower is probably 8 or 9 kW with the element in a space about the size of a cigarette packet.
I had electric showers in a hard water area and they started to behave oddly including symptoms similar to yours. It wasn't a faulty thermostat, the thermostat was behaving correctly but acting to prevent overheating in a scaled up element.
I couldn't find a way of descaling or replacing the heater element. I replaced the entire unit, then that scaled up a couple of years later (it was heavily used). I got a third one and installed a water softener which seemed to do the trick - it lasted till I sold the house.
I have just had to clean the filter on ours to cure exactly the same
symptoms - once cleaned the problem was solved. Ours looks slightly
different but is a Mira Sport - 9KW I think.
Two screws on top, one on the bottom. Ease off the cover and then the
cover on the left side. Carefully undo the plastic hex filter. I found
an orange tube which I put under the tap to discover the orange colour
washed off to leave a fine clear plastic mesh. I don't know what the
orange was but it was obviously impeding the flow.
Lose (rhymes with fuse) is a verb, the opposite of find. Loose (rhymes
They don't have a thermostat, temperature is controlled by the number of
elements turned on and the water flow (set by the flow restrictor -
temp control knob).
If it's over temp at maximum flow then there is either low pressure or a
flow restriction so look for anything that would reduce flow, like a
blocked input filter. You say you have soft water so it shouldn't be
either limescale internally or on the shower head. Try removing the
shower head to see if water flow improves. Have you noticed a reduction
Also, I assume no-one has had the front off? The knob for the temp/flow
control usually disengages when the front panel is removed and failing
to re-assemble it in the same position could result in less than normal
flow at the max posn.
From your link to the actual shower, it's not cheap crap so well worth
 There are 2 elements of roughly equal power, high is normally both
on, medium is one on and low is neither on.
 shower head blockage would be v bad as it will pop the over pressure
safety device in the heater
No change in flow as far as I can tell... However, I just tried the tip
about removing the shower head (no effect BTW), and the "Low Flow"
indicator came on briefly when setting was on High with lowest temp.
Never seen that light coming on before. Is that a further clue as to the
No one touched it - I am sure of that. I fitted a fair few of those
several years ago, so am very familiar them.
That's also what I thought. It is just that the idea of messing about
with something electrical that is all but under water, and with you
standing in a puddle next to it, makes me very uncomfortable.
I can understand your caution and it is understandable, a shower is a
scary appliance, high current, exposed terminals and water to boot but a
properly installed one will have a double pole isolator before it which
you can and should use to make it safe before opening the case. You can
also switch it off at your consumer unit for that extra feeling of
Download the installers manual for extra confidence on the correct way
to open and dismantle it. It should show you where the filter is
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