Maintenance And Service; Oil; Pump Construction; Cleaning The Pump - Grundfos Unilift AP35B Installation And Operating Instructions Manual

10. Maintenance and service

Warning
Before starting work on the pump,
make sure that the power supply to the
pump has been switched off and that it
cannot be accidentally switched on.
During dismantling, caution should be
exercised as there will be access to
sharp edges, etc. which may cut.
Warning
Before carrying out maintenance and
service, make sure that the pump has
been thoroughly flushed with clean
water. Rinse the pump parts in water
after dismantling.
Check the pump and replace the oil once a year.
If the pump is used for pumping liquids containing
abrasive particles or it is operating continuously,
the pump must be checked at shorter intervals.
Warning
Out of consideration for the personal
safety and health, this work must be
carried out by specially trained
persons.
Furthermore, all rules and regulations
covering safety, health and
environment must be observed.
A possible replacement of the cable or
the float switch must be carried out by
an authorised Grundfos service
workshop.

10.1 Oil

The pump contains approx. 2 oz. (60 ml) non-
poisonous oil.
Used oil must be disposed of in accordance with
local regulations.
If the drained oil contains water or other impurities,
replace the shaft seal.

10.2 Pump construction

The main components of the pump appear from the
table below and figure B on page 30.
Pos. Description
6 Inlet part
26 Spring clamps
37, 37a O-ring
49 Impeller
50 Pump housing
66 Washer
67 Lock nut
84 Ring stand
105a Shaft seal
150 Motor
182 Cable entry
189, 190 Pump handle
193, 194 Screws

10.3 Cleaning the pump

If the pump does not deliver a sufficient quantity of
water because of sediment, dismantle and clean the
pump.
To dismantle the pump, follow this procedure:
1. Disconnect the power supply.
2. Allow the pump to drain.
3. Remove the pump housing (pos. 50) by inserting
a screwdriver into the slot of one of the four
spring clamps (pos. 26) and pressing downwards
until the clamp comes loose. Repeat the
procedure for all four clamps.
4. Clean the pump housing, the pump, and the
impeller (pos. 49).
5. Check to make sure the impeller can rotate freely.
If not, remove the impeller:
– Hold the impeller in place with a screwdriver
while loosening and removing the lock nut
(pos. 67) on the motor shaft.
– Clean the impeller and around the shaft.
6. Check the impeller and around the shaft. If the
impeller is worn or defective, replace it.
7. Assemble the pump in reverse order of
dismantling:
– Fit the impeller (pos. 49) with the washer and
lock nut (pos. 67). Make sure the impeller
engages with the shaft.
– Place the inlet part (pos. 6), the O-ring
(pos. 37), the pump housing (pos. 50) and the
O-ring (pos. 37a) on top of the ring stand
(pos. 84) and lower the pump onto this
assembly.
– Fit the four spring clamps (pos. 26) using a
screwdriver.
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