Here is something we do as a matter of course following a sweep, a type 2 smoke test, which checks the draw of the chimney and whether there is any smoke spillage into the room. The chimney is warmed with a firelighter (my preferred option – A cold chimney will not draw and there is no heat in a smoke pellet, so the chimney must be warmed prior to smoke testing), all windows and doors in the room are closed so that there is no additional draft. A smoke pellet is placed into the inside of the stove or open fire. All smoke should remain inside the stove and be seen leaving the pot, also smoke in an open fire should be seen entering the flue and leaving the pot. No smoke should be entering the room from the stove or open fire. If this is not the case, for example smoke is observed to exit a number of pots or enter upstairs room then the chimney has failed and further investigation is required, i.e. a type 1 integrity smoke test and/or CCTV investigation.