Grundfos CM series, Service Instructions Manual

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5.8 Checking and replacing impellers and chambers
Check Replace
Impeller Wear ring/wear ring retainer
• Check whether it is necessary to replace the impeller due to fric-
tion between wear ring and impeller skirt. If wear has caused a
noticeable (use a finger nail) groove in the impeller skirt, the im-
peller should be replaced.
It is advisable always to replace wear rings (pos. 45) and wear
ring retainers (pos. 65) when the chamber stack is dismantled.
1. Prise the wear ring retainer (pos. 65) up and free of the chamber
using a screwdriver.
2. Remove wear ring (pos. 45).
3. Fit a new wear ring in the chamber. See the figure below.
4. Press a new wear ring retainer on the wear ring and into the cham-
ber.
It must be possible to move the wear ring freely (sideways) between
the retainer and the chamber.
Bearing ring
• Check whether there is a visible and noticeable (use a finger nail)
edge on the rotating bearing ring. • Replace both bearing rings (pos. 47a) and chamber for bearing
(pos. 4a).
TM021
182
Correct fitting of wear ring
5.9 Replacement of impellers and spacing pipes
Replace all impellers and spacing pipes. If new impellers
or spacing pipes are installed in combination with old im-
pellers and spacing pipes, the pump will not run optimally
and it may malfunction.
Based on production date, different impellers and spacing pipes
have been designed for CM, CME pumps. New impellers and
spacing pipes are therefore not interchangeable with old impellers
and spacing pipes.
Therefore, Grundfos offers impellers and spacing pipes as complete
service kits, including the specific quantity and type of impellers and
spacing pipes for all CM, CME pump models.
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English (GB)