The hot water from my Worcester 240 is not as hot as it use to be.Central heating is ok and when heating is on,the temp of hot water also improves considerably.The system is about 10 years old and has been trouble free until now.It didnt just suddenly happen but has slowly got worse over a few months.

JOHN SKINNER, April 2005

There is your problem in the description, the water heat has dropped off over a period of time, I would suggest it is the secondary heat exchanger that is becoming blocked on the central heating side, remove it an power wash it out.

Wrekin Gas, July 2006