by htg engineer »
Fri May 15, 2009 3:42 pm
It could be many things and hard to diagnose without hearing it or seeing the boiler, the best advice I can offer is for you to get an RGI in to repair, it may juts be a washer or O ring needing replacing on the diverter valve, this happens on the Baxi Combi, but more of a a whining noise.
Could be a faulty valve or just a pipe or boiler case vibrating.
htg