I have Potterton Suprima 60 boiler that when I turn the central heating on
makes an annoying droning noise that reverberates throughout the house. It
does not make this noise when the hot water is on only when I want the rads
to come on. The noise will last a few minutes then die away but when you
think all is OK it comes back again a bit later. The noise does seem to come
from the boiler rather than the pump. I am pretty sure the pump is working
as I can feel a slight vibration that increases when you up the setting for
the pump. Also the rads do heat up quite quickly.

It started to make this noise last winter so during the spring I flushed the
system.

The boiler is not that old. The previous owner of the house had it installed
by British Gas 2 1/2 years ago.

Anyone got any suggestions?

Eric.