It very much depends on where its actually coming from, both ideas here
could be the case, and my neighbour had a pump that occasionally shifted and
made contact with a wall, transmitting the motor buzz all around the house
and also here next door.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"alan_m" wrote in message
...
On 15/01/2021 00:03, JohnP wrote:
Kjh wrote in
roupdirect.com:

We have had a new Worcestershire Bosch 30i boiler. We have found
during the day when room stat is set to 18 deg no problem, at night
when we increase room stat to 22 deg there is an occasional humming
noise and it stops when we turn the hot tap on.


Flow resonance - try adjusting some lockshield valves to shange the flow.
Read up on "Balancing a Central Heating System" Could be a thermostative
valve being nearly closed and vibrating in the flow.


I had something similar and cured by slightly reducing the gas flow to the
gas burner.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk