Where does your boiler flue exit the building?

You may need to check the outside of your property to confirm

Wall

Slopped Roof

Flat Roof

About Flues
A boiler flue is a pipe that carries exhaust gases produced by your boiler it into the atmosphere.

If your boiler is fitted to an exterior wall, then you probably have a wall flue. If your boiler is fitted to an interior wall then you will probably have a flue that exits through the roof, which will either be sloped or flat