Power Button: press and hold for 2s to switch on/off the machine, after switching on the machine it will be in minimum suction mode, press to suspend the working mode, press again to resume the working mode, and so on. Pressure relief key: In the suction mode, press and hold to keep the pressure relief mode, and release to keep the suction mode. Pressure reduction key: Tap to reduce the pressure. Pressing key: Tap to increase the pressure.