This sounds like you are going to need a new cartridge.
To check wither you have a boiler or shower fault
Turn the shower on as usual, try and get a hold of the pipe going to the shower, if you can’t get to hold the pipe at the shower you may be able to get to it as it leaves the boiler.
What ever the temperature is on/in this pipe, the shower can never get any hotter than that (So if the temperature is cool then something then at the boiler is not allowing the water to heat up enough)
If the temperature is hot then you need a new cartridge.
Here is the link
Answered 12 years ago by Anonymous
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