The gauge indicating the regulator cavity pressure, The gas in the gegulator can only be released from the needle valve, only the gas in the regulator cavity be released the pressure can go down.When you turn the knob of the to turn down the pressure, the gas in the regulator can not be released timely, the gauge indictor  don't goes down. If you need turn down the output pressure. Please see the following steps: 1. Turn the knob to the end of the mininum positon.2. Power on and turn open the needle valve to release the gas in the regulator. The output pressure will  reduce to be zero3. Turn up the knob till to the pressure you need.