In article , says...

Capitol wrote:

If the boiler is working have it serviced and leave it alone.

Um, no. Not in this case. If it's "pumping over" as this one sounds to be
doing it needs sorting fairly urgently. Otherwise you'll have a damp loft
and a lot of wasted heat.

System probably needs a flush and a check over for correct plumbing.
Reducing pump speed will probably help in the short term.

See
http://www.diyfixit.co.uk/central-he...open-vent.html

Tim

Thank you for the link, Tim - very useful.

--

Terry