OPEN IMPELLER O011
|The impeller vanes are not enclosed between shrouds. They attach to, and are supported by the hub of the impeller.
The open impeller has to be adjusted to either the volute or backplate to prevent internal re-circulation of the pumpage.
A clearance of 0.015 to 0.020 inches (0.4 to 0.5 mm) between the impeller vanes and the volute or back plate would be typical, but check with your manufacturer to be sure.