Unscrew this, remember follow the clock wise

If you just want to replace worn out impeller: hold the limiter steady, unscrew (red square) with clock wise, take out the inner burr. And try to clean and replace the impeller while holding the limiter! You should ask some body to help with this step.

Take the Limiter out. Take care because it go with 6 balls and 6 springs! Perform this step only if you think there are some wrong with the Limiter (Big crack sound when grind )