After replacing pump problems occurred

[voicey]

This might sound stupid but is the pump valve open ?

Assuming you mean the valves above and below the pump then yes. I'll try the shutting down each rad tomorrow as I can't be arsed at the moment. Thanks for the suggestion.

it is worth checking your open vent/cold feed are round the right way.

I haven't checked this but assmumed that everything was OK. I've been in the flat for 3 yrs now and not had any probelms, apart from the noisey pump which has led to this problem.

I'm thinking that the new pump, being more powerful, might have dislodged a bit of cr*p sealing a leak thus causing the problem?????

 

[voicey]

Problem Solved (I hope!)

After giving up yesterday I woke this morning to find the system in perfect working order. I think turning the pump down to 2 and then bleeding the remaining air out has sorted it. Thanks to all who helped.