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Oct 21, 2022
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York
Member Type
DIY or Homeowner
I have recently fitted a thermostatic external mixer shower in my bathroom. The problem is that when it is set to the highest possible temperature its only luke warm at best. The hot water in my house is generated from a combi boiler which should be able to deliver a hot water flowrate of 12.5L/min. The boiler doesnt seem to be the problem as both bathroom and kitchen hot water taps in the house produce hot water without issue, and the boiler was only serviced last week.



I have checked that the cold/hot water pipes are the right way around into the shower bar and i have tried to calibrate the hot water delivery from the bar buy removing the temperature control knob and adjusting it but it already seems to be at its highest setting.



Does anyone have any other ideas? Id say im a DIY enthusiast but this has me stumped! Shower and boiler details in my house are posted below.



Ripley Round Thermostatic Dual Head Shower Set in my bathroom



IDEAL HEATING LOGIC MAX COMBI C30 GAS COMBI BOILER
 
Common causes of this are:
1) not enough flow to fire the boiler
2) cold crossing into hot supply pipes, effectively causing 1 also.

Solutions
1) i) valve somewhere not fully open
ii) blocked inlet filter at shower (hot)
iii) hose/head too restrictive

2) faulty or missing non return valves
 
This question, word for word, has already been asked and answered:

 

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