radiators hot, water only lukewarm

[bestest]

hi, i have a 17yr old ferroli optima combi boiler. i have BG cover and i'm forever calling them out. they tell me i need to change boiler. at the minute my rads are piping hot but the tap water and my combi shower only get warm. why is this, will a new boiler solve all problems. all my bathroom is new so i'm guessing there's no probs with the shower itself. just can't understand how rads are hot but the water from taps and shower is only warm. plz plz advise (i really miss my hot showers)
mny tx

 

[cross thread]

get them back out and get them to check water flow rate .gas pressures and if they are ok hot water thermistor,

 

[BARNY78BG]

is your heating on when you are using your hot water? agree with gordengas get bg out as they'll always advise a new boiler cause of it's age(if it's 12 to 15 yrs old, so if parts are available then it should be fixed