chris sanders
I'm assuming it was a Bg engineer ? He should remove the cover to visual inside and also to check the the gas pressure at the boiler. Using an analyser only checks that the boiler is producing the correct ratio between co & co2. It may be that he did not service the boiler but only did a gas saftey check these are two different things but with both you should be a little more thorough. The best thing is to complain to the company who carried out the work and if you get no joy from them call gas safe and make a request for a free inspection of the work carried out
