Alamarin Jet COMBI-FRAME AJ 285 Repair Manual page 35

Impeller
Repair manual
Figure 41. Position of the keyway
The thrust caused by the impeller is transmitted through the adjuster
sleeve to the shaft (figure 42, point A). The sleeve consists of rings of
different thickness. The length of the sleeve can be adjusted in 0.5 mm
(approx. 0.02") increments by changing the number of the rings. This way
the impeller gap on the outer race becomes fit.
KM/285/EN/1.1.0 31