What causes the excessive noise from a Britony Flexi Flue boiler? The boiler works OK but the noise is a persistent drone off the boiler, even when the boiler is off. This noise is increasing. Any suggestions as to what may be wrong with it and how to fix it - also, is it safe?

HC Woodward, November 2010

If it's what I'm thinking, it's quite safe.
Sounds like the fan (runs 24/7) low speed when not in use to keep the pilot light going.
Get hold of an RGI to check the fan out, repairs are not an option, replacement only.

Carefree, November 2010