Mixer Shower - Mira Platinum

8 Jun 2006
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United Kingdom
Boiler it's working off at the moment is a Ferroli Maxima 35c

Shower installed, it runs for a while and then goes cold and repeats the cycle and yet the hot water to a bath/tap retains it's heat.

The showers maximum temp is 48 and the boilers is 55 ..I usually keep the boiler at 45 for hot water as 55 is far too hot.

The water pressure/shower pressure is excellent but I cannot get the shower temperature to remain constant, it simply goes cold for a while then heats up a little bit but not to 45..and then goes cold again.

It's a new shower..

Any ideas?
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who fitted it ?
how longs it been fitted ?
is the boiler constantly firing up or cycling on/off ?

As for your comments
some of us have better things to do on christmas/boxing day than worrying about plumbing problems. :rolleyes:
yes and over two pages of replies says there are others that are not etc.

It was fitted by a company who are off until 4th Jan

The boiler remains constant when the shower is in operation

It was fitted on 23rd, they didn't fully check it when it was fitted due to it being close to the end of the day...
It was fitted by a company who are off until 4th Jan
the ball falls in their court then if they don't come round call mira out under warranty and if its a install issue you will be charged then pass the bill on to the fitters. don't tamper with it yourself.

The boiler remains constant when the shower is in operation
thats ok.

It was fitted on 23rd, they didn't fully check it when it was fitted due to it being close to the end of the day...
end of the day is when the jobs complete not half way through it.

it can be a number of issues.
temp of incoming mains.
what flow restrictors where fitted depending on boiler kw/btu.
Thanks for coming back to me.

The ball is in their court save if the boiler is an issue I guess.

Boiler is a 35kw ..will be changing the boiler quite soon.

What I can see is that the shower comes with a couple of coloured valves...or rather plastic washers, they tried it without the washers which is for a boiler over 30kw...they then put in one of the coloured washers (onto the mixer unit as specified in manual) but they have put the washer in for a much lower rate boiler. I would have taken it out but as you also advise it's for them to do not me hence why I haven't touched it...but even so, they tried it without and it made no difference.

The mains pressure is excellent here but the shower is approx 10m from the boiler... pipework wise as in the bath taps and with any water to a bath I have to keep the taps fairly low so as to get the water hot...if I have them on a reasonable flow the water tends not to get very hot even when they've been running for ages...so keeping them on a low flow gets the water red hot....I'm just wondering if this is the same for the shower and that actually the boiler isn't up to scratch and cannot deliver what it should when it's called up to do so. I've since purchased a new boiler and am currently looking at getting it fitted very soon....but is the above paragraph consistent with combui boilers or is my boiler perhaps faulty in some way?
should say the Ferroli will be coming off the wall any time soon as...I'm just waiting to source a competent plumber ...the ferroli flue has been leaking and I only switch it on intermittently ...the boiler works ok but the flue is leaking and their has been water damage on the boiler itself but when it fires up apart from water from the flue dripping everywhere the boiler itself works...I just couldn't source the parts easy enough and given that water has been everywhere and there is corrsion inside then a boiler change is required etc. Thankfully my knight in shining armour bought a boiler priot to Xmas.

But, the ferroli when it's switched on works as it should it's just that i dont keep it switched on due to flue problems.
id turn it off and leave it off, you could be very close to not seeing in the new year, as for the shower, ive a feeling its thermostatic and if so is probably limited by the manufactures to 48 degrees, have you actually measured the water temp from the shower? you certainly wouldnt want to shower in anything over 50 as you would come out like a lobster
thanks for the reply, yes 48 is it's maximum but 40 is where I suspect it will be but it gets hot for a short amount of time and then goes altogether cold and then gets a little warmer again etc.....
Julie G

I know your post is an old one, but I am having the same problem as you with a mira platinum fitted in December 2012.

I have a new boiler which works fine but the shower is rubbish no better than my old 7kw electric. Will not maintain starting temp or pressure. Mira engineer came out changed mixer valve which stopped the racket and vibrating pipes, and I thought the problem was fixed now I seem to have a new one, wondering if the radio controller is faulty. New visit arranged think I will be charged this time, wouldn't mind if they at least offer a diagnosis but the last guy couldn't, hence the valve change. Had the shower since Dec 20 not had decent shower yet.

I am also in the same location as you, did you ever solve the problem.

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