Central heating problems - continued
 

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

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.

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

To email, substitute .nospam with .gl

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.

I would have some minor concerns about the relative positions of the
cold feed and expansion pipes in that strictly speaking, I would not
consider them "close coupled". Have you checked in case the cold feed
is blocked?. To do this,drain some water off the system (see if there
is a drain valve downstairs) and see if the ballvavle in the header
tank operates to top up as it drains. If not,suspect a blocked cold
feed in the area whre it connects to the system.

joe

Hi,

On CH2 the pipe going upwards from the bend on the right goes upwards
and is then capped with an air vent as you say. I think its a good idea
to go into the loft and see whats happening. Ive got a mate coming
around on Saturday who knows a little and I'll put your comments into
the mix and try and work it out. I'll also test the air coming out for
hydrogen.

On CH2, the pipe from the left of the motorised pump must feed the
radiators. However, where is the return to the boiler if this valve if
only the hot water is switched on?

Also, why is the pipe from the left of the valve connected to the pipe
going upwards from the pump?

I wonder why air gets trapped in this one radiator however? This is the
last radiator on the circuit.

Also, consider this. If the air is moving around the system (you can
hear it bubble through the boiler and a few seconds after that the pump
starts cavitating - so it is moving around) then it must at some point
go through the coil in the DHW tank. I appreciate this doesnt solve the
cause of the problem but is it possible to fit some sort of bleed
filter to the bleed valve at the 15mm pipe coming off the 22mm where it
enters the cylinder?

In addition, if air is getting in then this must be pushing water out.
I presume back into the expansion tank in the loft.

The only other thing I have noticed is that my towel radiator has a
slight leek. A couple of little drips that does build up to around 2
table spoons fulls of sugar over the course of the weekend. Could this
be the route of the problem?

One more question: which way would the water flow through the pump?
From top to bottom or pumped upwards from bottom to top.

Unfortunately I work away all week so I am limited to looking at the
thing in the limited time I get at home at weekends :(

CM.

On 22 Nov 2004 07:00:39 -0800, "Charles Middleton"
wrote:

Hi,

On CH2 the pipe going upwards from the bend on the right goes upwards
and is then capped with an air vent as you say.

OK, makes sense.

I think its a good idea
to go into the loft and see whats happening. Ive got a mate coming
around on Saturday who knows a little and I'll put your comments into
the mix and try and work it out. I'll also test the air coming out for
hydrogen.

On CH2, the pipe from the left of the motorised pump must feed the
radiators.

Yes.

However, where is the return to the boiler if this valve if
only the hot water is switched on?

The pipe coming across horizontally above the immersion is the return
from the coil in the cylinder. I can't see completely but I guess it
goes down through the floor behind the pump?

If so, then the return from the radiators will join it under the floor
and then go to the boiler.



Also, why is the pipe from the left of the valve connected to the pipe
going upwards from the pump?

Oh yes, I can just about see it in CH3.

Hmm.. shouldn't be. Perhaps it's blocked off. If you have the
system on DHW only, does the pipe to the left of the motorised valve
get warm above this join? How about below the join between there and
where it goes through the floor? Logically, this lower piece should
only get hot with CH running. If there is a way across, bypassing the
valve then the radiators would get hot whenever the ump runs.



I wonder why air gets trapped in this one radiator however? This is the
last radiator on the circuit.

It can happen anywhere- for example if the pipes slope under the
floor.



Also, consider this. If the air is moving around the system (you can
hear it bubble through the boiler and a few seconds after that the pump
starts cavitating - so it is moving around) then it must at some point
go through the coil in the DHW tank. I appreciate this doesnt solve the
cause of the problem but is it possible to fit some sort of bleed
filter to the bleed valve at the 15mm pipe coming off the 22mm where it
enters the cylinder?

You could fit an authomatic air vent in place of the bleed valve, but
it's not really a good long term solution. It's best to find the
problem and fix it.



In addition, if air is getting in then this must be pushing water out.
I presume back into the expansion tank in the loft.

With the pipe layout it shouldn't be. It could be that the roof tank
is empty and letting air in.




The only other thing I have noticed is that my towel radiator has a
slight leek. A couple of little drips that does build up to around 2
table spoons fulls of sugar over the course of the weekend. Could this
be the route of the problem?

It's possible that when the pump runs, air is sucked in here and when
it stops, there is a small leak out.




One more question: which way would the water flow through the pump?
From top to bottom or pumped upwards from bottom to top.

Normally it's upwards in this configuration.



Unfortunately I work away all week so I am limited to looking at the
thing in the limited time I get at home at weekends :(

CM.


--

..andy

To email, substitute .nospam with .gl

On Mon, 22 Nov 2004 15:29:10 +0000, Andy Hall wrote:

On 22 Nov 2004 07:00:39 -0800, "Charles Middleton"
wrote:

Hi,

On CH2 the pipe going upwards from the bend on the right goes upwards
and is then capped with an air vent as you say.

OK, makes sense.

I think its a good idea
to go into the loft and see whats happening. Ive got a mate coming
around on Saturday who knows a little and I'll put your comments into
the mix and try and work it out. I'll also test the air coming out for
hydrogen.

On CH2, the pipe from the left of the motorised pump must feed the
radiators.

Yes.

However, where is the return to the boiler if this valve if
only the hot water is switched on?

The pipe coming across horizontally above the immersion is the return
from the coil in the cylinder. I can't see completely but I guess it
goes down through the floor behind the pump?

If so, then the return from the radiators will join it under the floor
and then go to the boiler.



Also, why is the pipe from the left of the valve connected to the pipe
going upwards from the pump?

Oh yes, I can just about see it in CH3.

Hmm.. shouldn't be. Perhaps it's blocked off. If you have the
system on DHW only, does the pipe to the left of the motorised valve
get warm above this join? How about below the join between there and
where it goes through the floor? Logically, this lower piece should
only get hot with CH running. If there is a way across, bypassing the
valve then the radiators would get hot whenever the ump runs.

Yes, that short cross pipe is odd, and I can't quite see for sure how it
is connected. There is also a gate valve (1), visible in CH3, that
appears to be in the CH flow from the left of the motorised valve. Is
there any sort of valve in the short pipe? Another photo showing these
points more clearly would be ideal, or at least a confirmatory
description. Everything else appears to be as Andy describes it.

The hot water coil return also has a gate valve (2) which would be used
to balance the coil, but is only appropriate if the motorised valve is a
"3-way" type and the system controller allows for both CH and HW to be
on together. My guess is that the short horizontal cross pipe is an
incorrectly fitted attempt at a by-pass, and the gate valve (1) should
be in it and not where it is (or seems to be - it's difficult to tell
from the photos).

Regarding the gurgling noises, one cause could be a stuck ball valve in
the header tank in the attic, causing the tank to gradually empty if
there is a leak anywhere - and you say there is a small one. Andy has
already suggested checking there is water in the header. Push the
floating ball down and make sure this causes cold mains water to enter.

I wonder why air gets trapped in this one radiator however? This is the
last radiator on the circuit.

It can happen anywhere- for example if the pipes slope under the
floor.



Also, consider this. If the air is moving around the system (you can
hear it bubble through the boiler and a few seconds after that the pump
starts cavitating - so it is moving around) then it must at some point
go through the coil in the DHW tank. I appreciate this doesnt solve the
cause of the problem but is it possible to fit some sort of bleed
filter to the bleed valve at the 15mm pipe coming off the 22mm where it
enters the cylinder?

You could fit an authomatic air vent in place of the bleed valve, but
it's not really a good long term solution. It's best to find the
problem and fix it.



In addition, if air is getting in then this must be pushing water out.
I presume back into the expansion tank in the loft.

With the pipe layout it shouldn't be. It could be that the roof tank
is empty and letting air in.




The only other thing I have noticed is that my towel radiator has a
slight leek. A couple of little drips that does build up to around 2
table spoons fulls of sugar over the course of the weekend. Could this
be the route of the problem?

It's possible that when the pump runs, air is sucked in here and when
it stops, there is a small leak out.




One more question: which way would the water flow through the pump?
From top to bottom or pumped upwards from bottom to top.

Normally it's upwards in this configuration.



Unfortunately I work away all week so I am limited to looking at the
thing in the limited time I get at home at weekends :(

CM.


Phil
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