There is a rumbling noise from tank in the attic, how do I fix?
The central heating tank in the attic makes a loud rumbling noise at intermittent times of the day(but usually 0400ish in the morning). I've popped my head in the attic whilst it was rumbling once and the tank was bubbling hot. Is this an airlock!!! How do I drain the system.
Tom, October 2010
