"Ben" wrote in message
...
I turned on my (combi boiler powered) heating for the first time this
season a few days ago, and the pump made one hell of a racket. I was all
for calling out a plumber when I realised I hadn't bled the radiators yet.
A quick bleed of the top radiator (I have one higher than all the others,
so all the air ends up in that one) and the pump is near-silent again.

Interesting, what kind of racket?

I only ask coz I wouldn't describe the noise we get as a racket, just quite
loud.