In seperate post 'Drained central heating, wont fill up again' I was
helped with my problem when I drained the central heating and couldnt
get it to refil due to a blockage from sludge in the header tank.

We now have water in teh system and yesterday the hot water and central
heating were both working again (minus the downstairs rads which dont
get hot due to the sludge).

However, inbetween the system being drained and flushing the blockage
we turned on the hot water system(for 40 mins). We I returned home I
found the pump was ratteling and making a noise.

Post the fix, it all seemed to work fine until this morning when the
pump started thumping and then finely screetching.

I've opened the valve on the front of the pump, not sure if there was
air there but black water did start flowing out. Now as soon as we turn
on either the heating or water the noise starts and hte pump cuts out
after 10 seconds.. have we dry run the pump and knackered it?

Ct