On 21 Nov 2004 05:04:50 -0800, "Charles Middleton"
wrote:

Hi,

As requested by Andy Hall, ive put some pictures of my CH system on
line on a friends web space...

http://members.aol.com/mysteriouscities/

The pictures are reasonably large so apologies in advance for download
times.

The original problem can be read on this thread ...

http://groups-beta.google.com/group/...624e28d6cd9015


Looking at picture CH3, it appears that the feed pipe from the CH
header tank is the 15mm one that comes down, bends near the floor and
joins the 22mm below the pump. I would think that the flow from the
boiler is the 22mm that comes up through the floor, branches forward
and joins below the pump. THe 22mm going straight up (from which
that pipe is teed) is probably the vent pipe. This is a reasonable
way to connect these as they are close, both on the same side of the
pump and no restrictions between boiler and vent.

Looking at CH2, the feed to the DHW cylinder coil is running
horizontally and then to the top of the coil. However, there is a
15mm pipe going upwards from the bend on the right.
Where does this go? Is it also up into the loft and making an
additional vent over the header tank? I could see why this is done
because of the arrangement of the motorised valve. Some means to let
the air out is needed. It could also simply go up slightly and be
capped with an air vent which is opened to let the air escape when
filling. If it is going up and forming an additional open vent,
then this could be an issue because it is on the other side of the
pump. In that scenario, it is possible that there is pump over into
the header tank. That would lead to more oxygen etc. being
introduced into the system.

Could you go up into the loft and then get somebody else to put the
system through its paces - i.e. change thermostats to make the boiler
run etc? THis way you can check the behaviour of the vent(s)..
There should be about 50-75mm of water in the tank above the feed
connection point at the bottom when the system is cold - more when
hot.

Try altering the pump speed and see if this makes a difference.

THe gurgles and swooshing noises are typical of air getting into the
system and being pumped round.

I would investigate all of that thoroughly first.

Did you test the gas coming from the radiator vents?





Copy of orginal post below...

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.


--

..andy

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