yes they do have the collars mixed up looking at it that flue will JUST be connected.
ask to see the analyser print off on a vaillant i normally get around 0.003 with around 57-80ppm. Your boiler hasnt yet been commisioned due the stickers are still stuck o the top off the boiler
as said in other post only real way to correct is to lift boiler up or bring flue whole down (I would do this one)
Vaillant are very pedantic with installations and warranty eeven down to the cleaner and inhibator used
ask to see the analyser print off on a vaillant i normally get around 0.003 with around 57-80ppm. Your boiler hasnt yet been commisioned due the stickers are still stuck o the top off the boiler
as said in other post only real way to correct is to lift boiler up or bring flue whole down (I would do this one)
Vaillant are very pedantic with installations and warranty eeven down to the cleaner and inhibator used