I mentioned yesterday that my 3A fuse kept blowing, knocking out my
central heating. After looking at it a bit more closely yesterday the
central heating clock stayed on for hours while the heating was
switched off. When I switched the heating on it worked for about an
hour before the fuse blows again. The radiators warmed up and I got
some hot water.

Is this a sign that everything is working mechanically but something
is overheating over that 1/2 hour - hour?

I'm starting to think the pump must be it so I guess I should get a
leccy around to check it out