Shower drops in temp after 2 mins

[Diyer171]

Hi All,

So my shower (Mira excel)has just recently started fluctuating in temperature. Typically after about 2 minutes it slowly drops to lukewarm or cold, then after another 2 minutes it returns to hot. Initially I thought it might be the temperature cartridge in the shower but I felt the hot water copper inlet when the temperature drops in the shower and the copper also drops making me think that it might have something to do with our boiler, except that we left the kitchen tap running on hot for 10 minutes and that doesn’t lose heat. Any suggestions welcome. Boiler is a vaillant ecomax 828 if that helps and pressure sits at 1bar.

 

[Aquarius]

Try removing the shower hose, and check this first, could just be the thermostatic cartridge doing it’s job.

 

[Gasmk1]

turn on shower and watch boiler I suspect flow is not enough on Shower to keep boiler on

 

[townfanjon]

Probably one of the best shower mixers made , but if its the old model ( white plastic ) its getting on a bit . As above from the guys , if the boilers ok it’s potentially scaled up .
If you leave the temp control in the same place , try move it from H to C regularly.

 

[Diyer171]

Thanks for your reply, what am I looking at to see if there is enough flow from the shower? I’m guessing the pressure gauge?

 

[Diyer171]

Try removing the shower hose, and check this first, could just be the thermostatic cartridge doing it’s job.

Removed the hose, no buildup of lime scale or anything like that. Surely if the hot water inlet (copper pipe) is dropping in temperature before it reaches the shower then it mustn’t have anything to do with the cartridge?

 

[Jazzman]

I think its your boiler,I would say the internal heat tank needs descaling, about £80 by a heating engineer, The water is coming on to heat but as the thing is scaled up it gets too hot and turns off and will continually keep doing this..

 

[Diyer17111]

I think you might be right, we have changed the heat exchanger and that didn’t make any difference. So now we have a cleaner in the system. And are noticing some slight improvement after a week of it being in.