DIYbanter - View Single Post - Air brick confusion

S Viemeister

wrote:

The fireplace which is still in use exits through one of the four
chimney pots.
..............
...how can I tell whether there is simply one cavity in the chimney
breast
between the ground floor, first floor and attic meaning placement of
the vents is not critical; or two separate cavities meaning that the
attic air brick may simply ventilate the first floor flue but not the
ground floor if not placed correctly?

If you have four chimney pots, it would be unlikely that you don't have
four flues.