Hi Chris
What sort of hose are you using with the machine?
I used to be plagued with this awful screeching whistle when I used the black flexible concertenering hose.
when solution was being passed through the pipes it was fine, but when dry it was ear splitting.
Just a thought, try changing to a different pipe hosing.
If that fails then you could try changing the resinating frequency by slightly inhibiting the airflow.
If you think about it when you use your 2 fingers to whistle, the air flow from your mouth has to be an exact pressure in relation to the aperture of your fingers to make the resonating pitch sound. Like wise with the tool and the pipes, change or resrtict the airflow and bingo no whistle.
That is in theory, try putting it to the test and let us know if this load of bunkum works.
If all else fails you can allways resort to getting pretty earmuffs
Regards
Robert Olifent
