Hi
Could anybody help i've a combi boiler 30CXI and the water only runs lukewarm it goes hot for a while (10 seconds) then goes back to being just warm, my heating seems fine although i think it runs a little hot, no error alerts are appearing on the screen and the pressure reading on the bolier is fine, i've run through the manual fault finding turning on central heating etc and then water but it doesnt seem to run hot, i've rung the glowworm customer hotline and the lady seemed to think it was the thermister? but after reading the manual id have thought if this was faulty it would show me an F error? if i unplug one side of the thermister it shows this error? Any help or guidance i dont mind getting an expert in but i'd like an idea of what i'm talking about...
thanks for any guidance.

The water is the same at all the taps, when you say system water do you mean the water in the central heating side? if so it was a little dark when i removed a radiator recently? The actual hot water is clean. Whats is the HX, sorry if i appear niave i generally interested in how it all works together.

OK, thnaks for your help i'll give a plumber a call i just wanted to have a little understanding before calling in help. thanks again