1、 The auxiliary flue must be reserved. Every kitchen has flue, and the flue also has main and auxiliary flue. The main flue runs through the whole building, while the auxiliary flue is relatively independent. Generally, the lampblack in the home will go to the secondary flue first, and then enter the main flue through the hole on the partition, which can ensure that the lampblack in each household is isolated. If the auxiliary flue is directly connected to the main flue, it will cause smoke inversion or string due to low pressure.

二、施工細節要注意，管道越短越好。另外，為了不破壞原有的主副煙道，其開口方向不是隨意可以改的，一定要打在副煙道里面。

2、 Pay attention to the construction details. The shorter the pipeline, the better. In addition, in order not to damage the original main and auxiliary flue, the opening direction is not optional, and must be placed inside the auxiliary flue.

三、一些業主為了避免串煙問題，放棄原有煙道，直接在窗戶上開孔排煙，這樣做是可以的，但有幾點需要注意。在窗戶或墻面開洞之前一定要經過物業的同意；其次注意問題，一般排煙管末端是金屬材質的，如果開的洞太小，金屬傳熱可能會使玻璃炸裂，傷及行人，且煙管通向窗外，強勁的北風對著吹會導致油煙倒灌。更好將管道伸出去以后把管道往下窩，這樣還可避免下雨時雨水流進管道，并把風擋在外面。

3、 In order to avoid the problem of smoke, some owners abandoned the original flue and directly opened holes in the windows to smoke. This is OK, but there are several points to be noted. First of all, the consent of the property must be obtained before opening the window or wall; Secondly, pay attention to the safety problem. Generally, the end of the smoke exhaust pipe is made of metal. If the hole is too small, the metal heat transfer may cause the glass to crack and hurt the pedestrian, and the smoke pipe leads to the outside of the window, and the strong north wind will cause the oil smoke to pour backward. It is better to stretch the pipe out and then nest it down, so as to prevent rain water from flowing into the pipe when it rains and keep the wind out.