Turn off nozzle and then the supply. There must be no leakage at the device, hose or the nozzle.
关闭喷嘴，然后关闭供应水源。这时这种装置、软管或喷嘴上必须没有泄漏。
3
The ducting hose end set funnel indraft cover use in ventilator installation. The ducting hose else end set discal air exit of power and heat supply set installation.