Maintenance Schedule; Adjusting The Impeller Clearance; Replacing The Grinder System - Grundfos UNILIFT APG Installation And Operating Instructions Manual

8.5 Maintenance schedule

Inspect pumps running normal operation every 3000
operating hours or at least once a year. If the dry-
solids content of the pumped liquid is very high or
sandy, check the pump at shorter intervals.
Check the following:
• Power consumption
See the nameplate.
• Oil level and oil condition
When the pump is new or after replacement of the
shaft seal, check the oil level after one week of
operation.
Use MARCOL 152 ESSO oil or equivalent type.
Oil auto-ignition temperature must be above 180
°C.
• Cable entry
Make sure that the cable entry is wa-
tertight and that the cables are not
sharply bent and/or pinched.
• Pump parts
Check the wearing parts, for example, impeller
and pump housing. Replace defective parts.
• Grinder system and parts
In case of frequent choke-ups, check the grinder
system for visible wearing. If necessary, replace
the grinder system.

8.6 Adjusting the impeller clearance

For position numbers in brackets, see exploded
drawing in the appendix.
Proceed as follows:
1. Loosen the set screws fully (12c).
2. Gently tighten the screws (26).
3. Gently tighten the set screws (12c).
4. Loosen the screws (26) with at least three turns.
5. Tighten the set screw (12c) by 180°.
6. Tighten the screws (26) with a torque of 7 Nm.
Related information
8.8 Changing the oil

8.7 Replacing the grinder system

CAUTION
Sharp element
Minor or moderate personal injury
‐
Wear protective gloves when touching
the sharp edges of the impeller, grinder
head and grinder ring.
For position numbers in brackets, see the exploded
drawing in the appendix.
Proceed as follows:
Dismantling
1. Loosen the screw (44a) that holds the grinder ring
in place.
2. Loosen the grinder ring (44) and open the
bayonet socket by knocking or turning the grinder
ring 15 to 20° clockwise. See the figure below.
Removing the grinder ring
3. Gently prise the grinder ring (44) out of the pump
housing with a screwdriver.
Make sure that the grinder ring does
not get stuck against the grinder head.
4. Use a plier to hold the grinder head.
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