Biasi Riva Compact HE

[plumbbobshan]

Called to a customers house and fitted is a Biasi Riva Compact HE !!!! Heating working fine , hot water only run luke warm. Could it be the small sensor with 2 blue wires on the diverter valve or even a limed up plate heat ex ???
The manual is not very helpfull at all .

 

[fixter1]

check flow rate whats it like when tap is turn down abit.

 

[plumbbobshan]

the flow rate is very good , easy 10/15 lts per min . if i turn down the tap it gets warmer but not hot enough for a bath !