thanks for the reply tony, something else has just struck me,we had a meter change a few months ago,could this have anything to do with it and would the potterton engineer set the new gas valve with an analyiser?
I wondered if anybody could give advice on the following please? we have a promax 24sl boiler fitted less than 12 months ago.the boiler was fine over the last winter and this summer :shock: ,but since turning on the central heating it has developed a really load whistle that turnes into a howl...