I have installed two new Worcester 30 CDi System boilers at home.

All is well except the noise that comes from the radiators when the pump is working.

It is a humming noise. Like a murmur. It is the sound of the water flowing through the radiator or valves.

In the quiteness of the night it can be quite disturbing. Enough to wake people up.

With the older Vokera boilers that I had before, this noise was not perceptible.

In addition to changing the boilers, I gave a good power flush to the central heating system and put inhibitor.

Is this noise due to a higher water flow speed with these newer boilers?

Is there a way to reduce the noise without compromising the system efficiency much?

Thanks,


Antonio

"asalcedo" wrote in message
...

I have installed two new Worcester 30 CDi System boilers at home.

All is well except the noise that comes from the radiators when the
pump is working.

It is a humming noise. Like a murmur. It is the sound of the water
flowing through the radiator or valves.

In the quiteness of the night it can be quite disturbing. Enough to
wake people up.

With the older Vokera boilers that I had before, this noise was not
perceptible.

In addition to changing the boilers, I gave a good power flush to the
central heating system and put inhibitor.

Is this noise due to a higher water flow speed with these newer
boilers?

Is there a way to reduce the noise without compromising the system
efficiency much?

Thanks,

Change the flow rate and see if it disappears

We had the same problem immediately after new ch installed, but it
went away after a week. I figured it was bits of trapped air that
needed time to sort themselves out.
Same might happen for you.

If not, is it near the boiler, or in the radiator loops? You could try
isolating parts of the system by fitting isolator valves and see if
you can localise it.

tonyjeffs wrote:
We had the same problem immediately after new ch installed, but it
went away after a week. I figured it was bits of trapped air that
needed time to sort themselves out.
Same might happen for you.

If not, is it near the boiler, or in the radiator loops? You could try
isolating parts of the system by fitting isolator valves and see if
you can localise it.

You will get this on any system. There is always some outgassing from
the pipes. In practice the bubbles get carried to a local high point -
one rad always has a cold top. Bleed that, re-pressurise if needs be,
and robert is a relative.

This problem is becoming now a big issue.

More information:

If I close the valves in any radiator, it disappears in that radiator.


The radiators have been bled fully several times.

I do not think there is any trapped air in the system because a power flushing pump was used to do the power flush and since then no air has been let inside. The power flush pump would have easily removed any trapped air.

System does not lose any pressure and no new water has been fed in.


I believe the noise is similar to the noise that the boilers make when the pump is working. It is just amplified in the radiators.

The boilers are working fine, they are brand new and have been inspected by the installers and by two Bosch engineers recently for an unrelated issue.


The bigger the radiator, the bigger the noise.



It happens with all radiators in all four zones of the central heating system. The system has a total of 25 radiators.



The main inconvenience is in the top floor, where the bedrooms are.

There are four radiators on that floor. When all four of them are working the noise is lower. When only one or two are working, the noise is louder.


I have contacted Worcester tech support and they say that the pump speed cannot be altered. They only suggest that I bring in one of their engineers for a chargeable call but give little hope that the problem can be solved.

Any more ideas?


Thanks,

Antonio

asalcedo wrote:

Any more ideas?


Could it be a form of water hammer?