ok thanks i understand now should the engineer have checked this when he serviced it, i was surprised because he did`nt do alot to the boiler he ran the hot water went outside to the gas meter then went outside to the flue and that was it he did`nt even take the front off the boiler
Unfortunately alot of BG engineers dont take pride in the work they do and just do the bare minimum to pass safety checks and they are gone.