This question is regarding Mira Excel/Select Thermostatic Cartridge - 903.33

fitted a new cartridge but still water not hot

We replaced the mains shower cartridge from the shower doctor in our ensuite shower but with the Temperature on max level 9 water gets hottish briefly then goes cold - hot water works fine in the basin in the ensuite and the bath can also be filled with hot water. The combi boiler was serviced very recently. We have also had a mains pressure fitted as suggested by our plumber - still working.
Asked 8 years ago by Lorna
Regarding the temperature fluctuation or cool running, it could be a faulty cartridge. However to check this if you have the shower fed from a combi boiler, see if you can get hold of the hot supply pipe before it enters the shower or perhaps as it leaves the boiler.


If when holding this pipe the temperature fluctuates or goes cool, then the problem is not with the shower but more likely with the boiler, as the shower can only deliver what the boiler sends to it.

Disregard the temperature at the taps as they have a different flow rate.

Answered 8 years ago by Anonymous

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