Inspection; Overhaul - Grundfos DWK O 6.50.075 Montage- Und Betriebsanleitung

14.2 Inspection

Under normal operating conditions, remove the
pump from the tank and inspect it once every year.
Under severe operating conditions where sand,
fibrous material and solids are involved, do this once
a month.
The standard inspection procedure is summarized
below.
14.2.1 How to remove the pump
1. Hook the lifting chain through the pump lifting
bracket and lift so that the chain just carries the
load of the pump.
2. Loosen the bolts/nuts of the outlet pipe to drain
away possible water in the pipe.
3. Remove the bolts/nuts of the outlet pipe, and lift
the pump out of the tank.
14.2.2 Inspection of seal sensor
Check the resistance of the seal sensor with a
multimeter as shown in fig. 11.
Do not use a megger as this will damage
Caution
the control circuit.
TP TP
SS SS
Fig. 11 Resistance check
16
Oil replacement
After checking the resistance of the seal sensor,
replace the oil in the oil chamber.
1. Unscrew the oil plug. See fig. 12.
2. Tilt the pump with the oil filling hole pointing
20 KΩ
Fig. 12
3. Fill fresh oil into the oil chamber through the oil
14.2.3 Inspection of impeller and wear plate
Check the clearance between impeller and wear
plate. Recommended clearance is 0.3 - 0.5 mm.
Replace or repair as necessary.

14.3 Overhaul

Overhaul of pumps should be carried out by an
authorized Grundfos service centre.
A normal overhaul includes these points:
1. Disassemble and clean the pump.
2. Inspect and replace, if necessary, each
3. Carry out electrical test of the motor.
4. Replace worn-out or damaged components.
5. Reassemble the pump.
6. Carry out performance and functional test of the
7. Repaint and pack the pump.
Warning
When loosening the screws of the oil
chamber, note that pressure may have
built up in the chamber. Do not remove the
screws until the pressure has been fully
relieved.
downwards in order to drain the pump of oil. If the
drained oil is contaminated or opaque, this is an
indication of an impending mechanical shaft seal
failure. Replace the mechanical seal.
Position of oil screw
filling hole. Use lubrication oil ISO VG 32 Mobil
DTE 24 turbine oil 90 or equivalent.
component.
pump.
Oil plug