Grundfos NK Montage- Und Betriebsanleitung Seite 33

10.2.2 Oil-lubricated bearings
Fig. 29 Bearing bracket with oil-lubricated roller and double
angular contact bearings
Under optimum operating conditions, the life of roller and double
angular contact bearings will approx. 100,000 operating hours.
After that period, it is advisable to replace the bearings.
See section 12.1 Service kits.
To monitor the bearing condition, regularly
measure vibration levels using the SPM
Note
measuring points on the bearing bracket.
See section 6.8.1 Vibration level.
The bearings are lubricated with mineral oil. Intervals for oil
change as well as the required quantities are specified below.
Bearing
Initial oil change
temperature
Up to 70 °C
After 400 hours
70 °C to 90 °C
Diameter of
Bearing type coupling shaft
[mm]
42
Roller and angular
48
contact bearings
60
Changing of oil
Step Action
Place a suitable container under the bearing bracket to
1
collect used oil.
2 Remove the vent/filling plug and the drain plug.
After drainage of the bearing bracket, fit the drain plug,
3
and fill new oil. See section 6.7.2.
Check the oil level regularly during operation,
Note
and add oil, if necessary. The level must always
be visible in the sight glass.
Basic characteristics
Shell Omala 68
Viscosity grade
AGMA EP Gear Oil Grade
Old AGMA Grade
Viscosity:
At 40 °C (104 °F)
At 100 °C (212 °F)
Flash point, COC, °F
Pour point, °F
Subsequent oil
changes
Every 4400 hours
Every 2200 hours
Approximate oil
quantity
[ml]
850
1700
1350
Test method
ISO 68
68
2 EP
2
D 445 68 mm /s
2
D 445 8.8 mm /s
D 92 405
D 97 –15
Grundfos order numbers
Quantity
Product number
[l]
1 97526699
5 97526721
18 97526723
10.3 Monitoring equipment
It is advisable to take weekly readings of these parameter:
• vibration level (use SPM measuring points)
• bearing temperature (if sensors have been fitted)
• inlet and outlet pressure (use pressure gauges).
Alternatively, follow the maintenance plan laid out for your
application.
10.4 Motor
The motor should be inspected at regular intervals. It is important
to keep the motor clean in order to ensure adequate ventilation. If
the pump is installed in dusty environments, it must be cleaned
and checked regularly.
10.4.1 Lubrication
Pump bearings
The pump is provided with maintenance-free, greased-for-life
bearings. The pump has no lubricating nipples.
Grease specifications: See 10.4.2 Bearing grease.
Motor bearings
Motors up to and including frame size 132 have maintenance-
free, greased-for-life bearings.
Motors of frame sizes larger than 132 should be greased
according to the indications on the motor nameplate.
Grease spills from the motor may occur.
Grease specifications: See 10.4.2 Bearing grease.
10.4.2 Bearing grease
Lithium-based grease according to the following specifications
must be used:
• NLGI class 2 or 3.
• Viscosity of basic oil: 70 to 150 cSt at +40 °C.
• Temperature range -30 °C to +140 °C during continuous
operation.
11. Periods of inactivity and frost protection
Pumps which are not being used during periods of frost should be
drained to avoid damage.
Drain the pump by removing the drain plug. See fig. 26.
Do not tighten the priming plug and replace the drain plug until
the pump is to be used again.
Warning
Care must be taken to ensure that the escaping
liquid does not cause personal injury or damage
to the motor or other components.
In hot-water installations, special attention
should be paid to the risk of personal injury
caused by scalding hot water.
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