Our 38cxi mounted on a brick external wall shakes the house - but not all the time. It appears to be when the boiler tries to light, it starts as an intense low rumbling (like a freight train going past the front of the house) and then the rumbling gets faster as the intensity decreases, ending in a little zzzzzzip - sound.

Norman, April 2006

I've had exactly the same problem (new boiler and 2nd problem in 6 months). If only gloworm were as helpful as you!

Celia, January 2008

I think the reason you are getting rumbling from your boiler , its because you have air in your system , Go the radiator the one without the thermostatic valve on and bleed it , its the one usually in the bathroom, then repressure your boiler to 1/12 bar , if its not that make sure your automatic air vent on your boiler is open , its best to get an engineer to look at that , as its hard to locate inside your boiler. How long have you had the boiler installed? are you still not under guarantee?

steve, January 2007