The - and + signs indicate the variation of flow from the nozzle. More flow is important, the greater the impact will be strong and vice versa.
The marks + and – indicate the 2 rectilignes jets, the positioning between the two marks is used to modify the speed of rotation of the jet.
For a optimal impact force, the rotation of the jet should not be too fast, for this, the setting the piston mark must be positioned the side of the sign -.
It is better to make adjustments during operation.
You should not feel the vibration or hear rotation of the nozzle. If this is the case, reducing the rotational speed by moving the setting mark towards the sign -
Important : the adjustment is accurate, a modification of the adjustment stroke of 1mm can be enough to modify the rotating speed, the length of the jet and the impact force.