Biasi 24S boiler taking ages to heat up water. Any ideas?

[gemmcd]

Hi,
Could anyone give me any ideas as to what could be wrong with my boiler? I would really appreciate it.
I have a Biasi 24S when has been acting up for sometime. He central heating side of it is fine no problems at all. It is just when it comes to getting hot water. For sometime now (over the past few months) I have noticed that the water when you have the taps on full was getting colder and colder. Then this weekend you are having to run the taps for ages to get any hot water at all and even then it is hit and miss. The taps have to be running pretty fast to get the boiler to kick in.
Also a couple of months ago if the taps and the central heating were on at the same time the boiler was really loud. This only lasted a day or so and just when I was thinking about getting someone out to it it stopped. So I forgot all about it, until now. I don't know whether it is related?
Thank you in advance.
Gemma.

Sorry I forgot to say it is a gas combi boiler.
Thanks
Gem.

 

[mcmoby69]

sounds like the diverter valve has a perforated diaphragm. the diaphragm can be changed or just change the head of the diverter. without looking at it though cant be sure.