Hot water problem on a worcester 24i II

[dean2000]

I have a worcester 24i II combi boiler and i'm having a bit of a problem with it.
When you turn on the hot water the boiler kicks in as normal but after a few minutes the hot water goes luke warm and not as hot as it normly is.
I have changed the temp sensor and the DHW thermister but still the same.
Any idea,s ?

 

[boilerdoktor]

There's no 24 mk2 pal it's either a junior, 24i or a si mk 2! Thermistors extremely rare on worcesters to go. Need more info on what it does and what model