===INSTALLATION INSTRUCTION===
　When building a house, build a ventilating duct through toiletrooms on each floor to the roof of the house. At the top of each toilettroom a bye-pass is installed directly to the ventilating duct. The top of the gas cell shall be interlinked with the top of the toiletroom. The automactic swinging air interchanger is installed on the ventilating duct at the top of the house, fixed with expansion screws and sealed with cement paste. When installing the air interchanger, be sure to do so vertically to ensure swinging. Install firmly to prevwnt typhoon. The vertical standard is ZHQ-350 When the case of the swinging head is taken off, the central shaft is regarded as standard. As for ZHQ-200,the outside diameter of the barrel seat is regarded as standard.

Basic Facilities Introduced：
　The bye-pass can be made of PVC pipe.Refer to the drawing.The diameter of the bye-pass shall be smaller on the upper floor and bigger on the lower floor. The size of the diameter shall depend on the volume of the toiletroom, and the smallest diameter shall be larger than 100mm. The advantage of the bye-pass installed is that waster air doesn't flow backward to the upper toiletroom while air is being driven out of the lower toiletroom. Moreover, air in the upper toiletroom can also be driven out due to the principle of fluid dynamics. However, it can be done only after the installation of the automatic swinging air interchanger.