This has recently developed with noise being heard in every room of the apartment.
Symptoms: Turn on CH and let it run - absolutely fine for hours. Then I open HW for a few seconds and shut HW off. Now this combi boiler begins to hum. When HW is turned on the noise goes away until the tap is shut off at which point the noise resumes.
All TRVs are fully open. The DHW diverter valve was replaced about 4 or 5 months ago and the boiler has been faultless until a few days ago.
I've searched this forum for this topic without finding a conclusive explanation. My neighbour who is an experienced Vaillant adoring fitter says he's not experienced anything like it. So I'm welcoming the input of the wider community.
Thanks,
Adam
Symptoms: Turn on CH and let it run - absolutely fine for hours. Then I open HW for a few seconds and shut HW off. Now this combi boiler begins to hum. When HW is turned on the noise goes away until the tap is shut off at which point the noise resumes.
All TRVs are fully open. The DHW diverter valve was replaced about 4 or 5 months ago and the boiler has been faultless until a few days ago.
I've searched this forum for this topic without finding a conclusive explanation. My neighbour who is an experienced Vaillant adoring fitter says he's not experienced anything like it. So I'm welcoming the input of the wider community.
Thanks,
Adam
