I have an Ariston Boiler and there is a whistling sound coming from the oulet pipe which is driving my neighbour mad. I have had the boiler serviced and the engineer said he could not find any problems and that the boiler was fine. He said that the whistling was the air being pushed put by the fan and was normal. However it only started 4/5 weeks ago. Is this correct and is there nothing I can do?

Ronald, April 2010