Draught

I have a steep learning curve when it comes to my fireplace. I have eventually learned which knob is for the airing and the other one which is opening the shaft (haha, did you notice I managed to get the words knob and shaft into the same sentence...I am clever!). Anyway, I had the "incident" some months ago where smoke went into the flat and darkened the walls covering the fireplace. Yesterday the same thing happened, the air just turned and in 30 secs flat was filled with smoke. Tonight friend was pointing out that perhaps it was because the kitchen fan was on. Then I remembered that the neighbours having the housewarming said the same thing last Saturday. "We cannot have the kitchen fan on at the same time the fireplace is going". At the time I felt pity for them, after all, an expensive flat and you cannot be cooking at the same time you have the fireplace on. Now it dawned on me that I am in the same position. Darn! But sure enough, as soon as I switched off the fan, the fireplace was rockin'. Mind you, I'm gonna have the construction guys repaint the walls for free!