Ravenheat boiler - no hot water

[Drakone]

We've had this boiler for a few years now and its always had problems but now it seems its something I can't ignore.

Basically the central heating consists of lots of banging, we joke that there is a guy with a drum set in the boiler room. I'm guessing its the pipes have come up but yeah this was something I could ignore.

Then the hot water got twitchy, you had to blast the tap to get hot water.

Now the hot water has gone altogether.

I'm pretty sure its a Ravenheat CSI 120 going off google images, what do you guys suggest?

 

[dcawkwell]

Diverter valve and possibly pump problems.
Easily fixed.

 

[MisterBlonde]

Sounds like the diaphragm in the diverter valve has failed. the symptom for the hot water (running it fast in order to work) is a common one.
Only problem is access to the diaphragm, the whole valve usually has to come out, or gas valve removal is needed. either way, service kit=cheap, labour cost=not cheap

as for the other noise(banging) what does your pressure gauge say? if it is low, could be the pump as the other poster says.
or could be boilerstat too high or pipes not secure. depends on the severity of the noise