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