A: The temperature problem may be caused by the boiler flowrate.
See below for how to check.
Regarding the temperaturefluctuation or cool running it could be a faulty cartridge however to checkthis, see if you can get hold of the hot supply pipe before it enters theshower or perhaps as it leaves the boiler.
If when holding this pipe thetemperature fluctuates or goes cool then the problem is not with the shower butmore likely with the boiler as the shower can only deliver what the boilersends to it. #
Disregard the temperature at thetaps as they have a different flow rate.
If the pressures are reasonably balancedthen the existing cartridge can work OK and you only need to change it for apink cartridge if/when you start having problems.
However the boiler installer mayinsist that you need the combi cartridge before he is prepared to check forfaults elsewhere.
Answered 128 days ago | The Doc