I have a PowerMax 155 boiler (IMI Range) which makes a a loud whirring noise when the burner kicks-in first thing in the morning to heat up the water and the radiators. This resonance which sounds like a constipated cow moo-ing! - lasts for about 5-10 seconds before it quietens down The system is about 10 years old and has a header tank in the loft. Is this easy to resolve? (We haven't needed to use the alarm clock in ages!)