mtagrant wrote:
When operating the above pump vibrates and of course the attached pipes
also vibrate.As a result there is an overall background "hum" in the
house.
Is this normal or is there a problem with the pump?


Mine vibrates from time to time, but it stopped for a few years after
descaling the system. I think a build up of lime scale on the rotor has
unbalanced it again.


john2