The central heating in my house works very well, but there is a problem: When the pump is working some of the radiators make noise.

Other radiators are silent.

It is not a humming noise, but a noise of liquid flowing as in a stream of water in the mountains. It is somewhat loud, especially at the beginning of the pump running.

I thought it might be due to air in the system, but all the radiators are now fully bled.

The system is a sealed one with plastic pipes and aluminium radiators. It has been powerflushed well and inhibited.

Any idea of how to resolve this?

Thanks,

Antonio

"asalcedo" wrote in message
...

The central heating in my house works very well, but there is a problem.
When the pump is working some of the radiators make noise.

Other radiators are silent.

It is not a humming noise, but a noise of water flowing. Akin to the
noise of a stream of water in the mountains. It is somewhat loud,
especially at the beginning of the pump running.

I thought it might be due to air in the system, but all the radiators
are fully bled.

The system is a sealed one with plastic pipes and aluminium radiators.
It has been powerflushed well and inhibited.

Any idea of how to resolve this?

Thanks,

Antonio

I have had this problem, caused by nearly-closed thermostatic radiator
valves. Do you have them and, if so, does the noise stop when you open them
fully?

Stephen

In article , Stephen Mawson
wrote:

snip

It is not a humming noise, but a noise of water flowing. Akin to the
noise of a stream of water in the mountains. It is somewhat loud,
especially at the beginning of the pump running.

snip

I have had this problem, caused by nearly-closed thermostatic radiator
valves. Do you have them and, if so, does the noise stop when you open them
fully?

Stephen


I'm not the OP, but (a) I have exactly the same problem and (b) yes, I
do have some mostly-closed TRVs and the sound does indeed diminsh/stop
when I open them fully.

Am I doomed to having them open and wasting heat (albeit with a quiet
system), or is there a Cunning Plan?

Thanks - Peter

In an earlier contribution to this discussion,
Peter Kemp wrote:


I'm not the OP, but (a) I have exactly the same problem and (b) yes,
I do have some mostly-closed TRVs and the sound does indeed
diminsh/stop when I open them fully.

Am I doomed to having them open and wasting heat (albeit with a quiet
system), or is there a Cunning Plan?

Thanks - Peter

Some TRVs are directional, and *mind* which way the water flows through
them. If fitted the wrong way round, they are noisy. So check yours, and put
them at the opposite end of the radiator if they are wrong.

[Or swap them from vertical to horizontal (or vice versa) if they are the
type with two compression joints at right angles. Or, if they're the sort
with a moving bit inside which allows the flow direction to be configured,
move that to the other position].

Unfortunately, all of these remedies require a certain amount of system
draining.
--
Cheers,
Roger
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On Dec 8, 10:37*pm, "Roger Mills" wrote:
In an earlier contribution to this discussion,


You can add a chemncial to reduce the noise. Even normal inhibitor
reduces the noise quite a bit, but presumably you have that already.

There can still be a pocket of air in the rads, even when fully bled,
because the bleed screws are not usually right at the top.

Robert

In an earlier contribution to this discussion,
RobertL wrote:

On Dec 8, 10:37 pm, "Roger Mills" wrote:
In an earlier contribution to this discussion,


You can add a chemncial to reduce the noise. Even normal inhibitor
reduces the noise quite a bit, but presumably you have that already.

There can still be a pocket of air in the rads, even when fully bled,
because the bleed screws are not usually right at the top.

Robert


Yes, but the noise I was talking about is not related to air, but occurs
when water flows through 'directional' valves in the wrong direction, and
gets the innards vibrating.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Hello Robert,

I am with you, inclined to believe that pockets of air are the cause.

The system is inhibited to manufacturer's specifications, as per the Sentinel Quick Test.

I do have a chemical for boiler noise, but since the noise is not from the boiler I have not added it.

I do not have TRVs and all valves, except for a couple for balancing (that do not make noise) are fully open.

The fact that some radiators are dead quiet and others are not, all other things being equal (lack of TRVs, valves fully opened) and the fact that the noise is not a humming noise (like the one when a TRV is the wrong way around or valves are not fully open) makes me believe that there may still be some air trapped as the most likely option.

The question then is how to get that air out of the system if bleeding the radiators is not helping.

Thanks,


Antonio

"asalcedo" wrote in message
...

RobertL;2313386 Wrote:
On Dec 8, 10:37*pm, "Roger Mills" wrote:-
In an earlier contribution to this discussion,-


You can add a chemncial to reduce the noise. Even normal inhibitor
reduces the noise quite a bit, but presumably you have that already.

There can still be a pocket of air in the rads, even when fully bled,
because the bleed screws are not usually right at the top.

Robert


Hello Robert,

I am with you, inclined to believe that pockets of air are the cause.

The system is inhibited to manufacturer's specifications, as per the
Sentinel Quick Test.

I do have a chemical for boiler noise, but since the noise is not from
the boiler I have not added it.

I do not have TRVs and all valves, except for a couple for balancing
(that do not make noise) are fully open.

The fact that some radiators are dead quiet and others are not, all
other things being equal (lack of TRVs, valves fully opened) and the
fact that the noise is not a humming noise (like the one when a TRV is
the wrong way around or valves are not fully open) makes me believe
that there may still be some air trapped as the most likely option.

The question then is how to get that air out of the system if bleeding
the radiators is not helping.

Thanks,


Antonio




--
asalcedo

I have got one as well. The radiator has some sort of restriction as it
takes ages to get hot - even though every valve is open. When I took the
radiator off to decorate I found a restricted flow out of the return pipe.
( I was just checking - I did close the valves!)

One further piece of information: For the radiators that make noise, I can reduce or even eliminate that noise if I close one of their valves two to three full turns (still three to five turns left to fully close them).

In other systems, as other posters have said here, usually the opposite happens, i.e. noise goes down when opening the valves....