Before I go and do this I thought I'd ask here. My pump seems to be making
a bit of a racket whilst the system is warming up - the noise gets less once
the house is warm.

The pump is running at it's slowest speed. Is it safe to crack it up to 2
or 3 to see if that gets rid of the noise or am I likely to get burst pipes
or rads with the increased water flow.

Sorry for what looks like a completely basic question.

Thanks.

Dave.