... to connect the gas chuck, make sure it tighten up, and close down the knob switch to the position of "−", then ... to adjust the flame size3.To shut off: Close down the gas cartridge valve, until the flame is die ... out ,and then to close down the knob switch ,make sure there is no gas ... leakage in the trachea, and then hanging up the torch store in a cool ,well ventilated palce ...