heatline c24

[stevepen]

I have a heatline c24 condensing boiler.central heating works fine at 85'c,hot water will work at 65'c,but only if i reduce cold water flow rate to 40% of mains pressure,any higher and hot water is luke warm.any idea what the fault is at the moment it takes half an hour to run a bath.
Have replaced dhw sensor,diverter valve.
Cheers

 

[transam]

your boiler should be producing approx 9.6 litres a min' at a temp rise of 35degs C , e.g if the temp' of your incoming main is say 5degs C than u would expect 9.6 litres a min at 40degs C at 65degs the boiler would be working at its upper limit . If I apply the same criteria 5deg's C than u would have 5.72 litres a min at a temp of 65 deg C.