I had a Worcester 24i combi boiler installed about 18 months ago, and
it's been fine since then. Obviously I've not been using the radiators
for the last few months, but I've been regularly using hot water with
no problem at all.

However, this week, I started up my central heating, and noticed that
one of my radiators was cooler at the top than bottom, so just bled it
a bit to get the heat even. Thought no more of it. Then a couple of
days later, I start up the heating, and nothing. It doesn't light, and
I can't get hot water either when I turn on my taps. At this point I
also noticed that the water pressure level had dropped right off, so I
added more water in to get pressure back up to 1 bar.

Then realised that the reason I couldn't get it to light was because
the cut-off switch had popped up, so pressed that down, and then
everything seemed okay.

But now whenever I try to start up the heating, within a couple of
minutes, the pump's making quite a noise, and then the cut-out switch
trips again. However, it does appear that I can get hot water out of
the taps with no problem.

Am I right in thinking that the pump is only used for the radiator side
of the system, and that's why I don't have any problem with the taps?
And would the fact that the pressure dropped right off be the reason
why all this has happened. I have now checked all my radiators, and as
far as I am aware, I don't have any more air in the system.

Is this the kind of problem I can sort out myself, or is it likely that
I'll need to get an engineer in?
Thanks for any help that anyone can give me...

Gareth