Hi,

My central heating system seems to be making a number of funny noises...

- The pump sometimes speeds up and slows down - this is accompanied with
what I could call a vibration noise. Very low pitched and not very loud.
More like its coming from the pipes rather than the pump.

- At irregular intervals a loud-ish gurgling sound comes from the radiator
in the master bedroom. This is accompanied by a sound I would compare to
water running into the radiator. Almost as if I had taken the (imaginary)
cap of the top of it and poured water into it. A water on metal sound - like
its filling up but its full of water which a quick unscrew of the bleed
valve confirms.

- If you put your hand on the pipe work in the airing cupboard (when not)
hot, around every second you can feel something almost like someone is
tapping on the pipe - a slight movement. Perhaps "knocking" would be a good
description.

.... also ...

- The master bedroom radiator requires bleeding on around a two weekly
interval.

The system is (I'll describe as not sure on the exact description), Gloworm
Ultimate boiler, a [something] Gold pump, has hot water tank and a small
header tank in the loft. Is this an "open vented" system? The hot water tank
has a small tank on the top which I believe provides the head for the
system.

Thinking about it, is it fare to say that the only mechanical part of the
system is the pump so It might be worth replacing this?

Thanks in advance,

CM.