On Mon, 25 Oct 2004 13:51:11 +0000 (UTC), "Charles Middleton"
wrote:

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.

It could be the pump on its way out or perhaps air getting into the
system.


- 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.

There probably is *some* air, it's just that it takes two weeks to
gather a noticable amount.


- 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.

With the pump running? Otherwise pipes in another part of the system
which are getting hot or cool and are expanding or contracting.


... also ...

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

That's a fair bit and should be investigated.


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.

Could you elucidate a bit more.

Do you mean that there is a small tank in the roof and then separately
and somewhere else there is a HW cylinder with its own small tank
separate to the first?

In any case it's an open vented system, but if you only had a single
header tank on the HW cylinder doing everything then it probably means
that you have a Primatic cylinder and the way to proceed is rather
different.





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?

It could be, but there may be other issues. Can you comment on the
system first. Also important if you have a small separate tank in the
roof is whether there is enough water in it. Also the relative
positions of the vent pipe leading to and over this tank and the
feed/expansion pipe going from the bottom. It's quite important to
know where these join the main system, how far apart etc.





Thanks in advance,

CM.


..andy

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