Anyone good with strange noises from boilers? I have a Glow Worm II
boiler that has been making a racket for some time and I think I really
ought to fix it or get someone in. It started about 3-4 years ago, when
a noise reminiscent of whale song could be heard each time the main
burner came on. Since then, it has been getting louder and louder and
now it is a dreadful, screeching, juddering noise of varying pitch. The
noise seems to be coming from the flue and, for want of a better
description, it sounds like high pressure gas passing through a
restrictive aperture. I should mention that it only occurs when the
ambient temperature is low (at best guess, when less than 4 deg C). Any
ideas? Is there a valve that regulates exhaust gas flow in the flue and
could this be the problem? I had imagined that the flue would just be a
simple chimney.

Thanks in advance, Jim,