Replacing The Impeller - Jung Pumpen MULTIFREE AW1 Instructions De Service

and therefore also hinder the pumping operation.
This situation can also occur if the pump runs dry, pumps down
to a lower lever than that shown in the installation drawing, or
runs in "snore" mode during the daily test run.
In these cases, the pump housing must be ventilated by un-
screwing the "LUFT" sealing screw.
SERVICING
Maintenance and inspection of this product must be carried
out in accordance with EN 12056-4 and EN 60074-19.
To ensure continued reliability of service, we recommend that
you take out a service contract.
WARNING!
Before carrying out any works: disconnect the pump and the
controls from the mains and take steps to ensure that it cannot
be emergized again.
WARNING!
Check the mains cable for signs of mechanical and chemical
damage. Damaged or kinked cables must be replaced by the
manufacturer.
NOTICE! When using a chain to lift the pump, please observe
the relevant national regulations regarding accident preven-
tion. Lifting gear must be checked regularly by an expert in ac-
cordance with the legal regulations.
NOTICE! Motors in the Ex-range conform to the "flameproof
enclosures" ignition protection category. Maintenance works
that affect the explosion protection may only be carried out by
authorised specialists or by the manufacturer. When carrying
out repairs, all areas next to flameproof gaps must be checked
for damages and, if necessary, replaced by genuine parts.
Oil check
The oil reservoir is sealed on the outside with a sealing screw
"OEL" (oil). In order to check the mechanical seal, the oil, includ-
ing any residue, must be drained from the oil reservoir and col-
lected in a clean measuring container.
• If the oil is contaminated with water (milky), an oil change
must be carried out. Check again after a further 300 operat-
ing hours, but at the very latest after 6 months!
• However, if the oil is contaminated with both water and pol-
lutants, then not only the oil must be replaced, but the me-
chanical seal as well.
For monitoring the oil reservoir, it is also possible to retrofit
the electrode of our "DKG" or DKG-Ex" seal leak control device
in place of the "DKG" sealing screw.
Changing the oil
To ensure operational liability, the first oil change should be
carried out after 300 operating hours, with further oil changes
carried out after every 1000 operating hours.
If the number of operating hours is very low, an oil change
should still be carried out at least once a year.
If wastewater with strongly abrasive constituents is being
pumped, the oil changes should be carried out at correspond-
ingly shorter intervals.
Use HLP hydraulic mineral oil, viscosity class 22 to 46, e.g. Mo-
bil DTE 22, DTE 24, DTE 25, to replace the oil in the oil reservoir.
The quantity of oil required is 1000 cm³ for pumps 10-45... and
1700 cm³ for pumps 55-100...
NOTICE! The oil reservoir may only be filled with the specified
quantity of oil. Overfilling will result in the pump being rendered
inoperable.
Cleaning
To clean the vortex impeller and the ring housing, simply re-
move the hexagonal screws just above the ring housing and lift
the motor unit off the ring housing.
CAUTION!
Worn impellers can have sharp edges.
NOTICE! If the wrong screws are unscrewed, the oil will run out NOTICE!
of the oil reservoir.
Tightening torque M for A2 screw materials
A
for M 6 M = 8 Nm
A
for M 8 M = 20 Nm
A
for M 10 M = 40 Nm
A
for M 12 M = 70 Nm
A
for M 16 M = 160 Nm
A
Checking the pump unit
The housing screws for the pump, and the connecting and fix-
ing screws of the installation must be checked to ensure they
are fixed securely. They should be tightened if necessary.
If the pump performance decreases, or if increasingly loud
noises can be heard during operation, the open centrifugal im-
peller must be checked for wear by an expert and replaced if
necessary.

Replacing the impeller

CAUTION!
Worn impellers can have sharp edges.
1. Remove the 4 hexagonal screws and lift the motor unit off
the ring housing.
2. Block the impeller to prevent it from turning.
3. Loosen the central impeller screw located in the impeller
hub.
4. Loosen the impeller by knocking it gently with a hammer and
then slide it off the shaft (use wedges or pullers if necessary).
5. Clean all the parts of the impeller mounting.
6. Grease the shaft cover on the inside.
7. Fit a new feather key in the shaft keyway and grease it.
8. Slide the new impeller right onto the shaft.
9. Immobilise the rotor and tighten the central fastening screw
as specified in the torque table. No adjustment is needed to
the impeller.
10. Mount the motor unit on the ring housing; the cable entry
point is opposite the discharge branch.
ENGLISH
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