Maintenance; General Instructions; Operation; Mechanical Shaft Seals - Grundfos Fire NKF series Montage- Und Betriebsanleitung

12. Maintenance

Warning
Before starting work on the pump, make sure that
the power supply has been switched off and that
it cannot be accidentally switched on.

12.1 General instructions

The operator is responsible for ensuring that all maintenance,
inspection and installation work is performed by qualified
personnel. A regular maintenance plan will help avoid expensive
repairs and contribute to trouble-free, reliable operation.

12.2 Operation

The pump is maintenance-free.
If the pump is to be drained for a long period of inactivity, inject a
few drops of silicone oil on the shaft at the bearing bracket.
This will prevent the shaft seal faces from sticking.
If the pump is started up due to a false alarm, it should operate for
maximum 48 hours. After prolonged false-alarm operation,
always dismantle the pump and inspect it for signs of wear or
damage. If necessary, replace any defective components.

12.3 Mechanical shaft seals

Mechanical shaft seals are maintenance-free and nearly leak-
free. In case of considerable and increasing seepage, check the
mechanical shaft seal immediately. If the seal faces are
damaged, replace the entire shaft seal. Handle mechanical shaft
seals with the greatest care.

12.4 Motor

Inspect the motor at regular intervals. It is important to keep the
motor clean to ensure adequate ventilation. If the pump is
installed in dusty environments, clean and check it regularly.

12.5 Lubrication

12.5.1 Pump bearings
Depending on size and model, the pumps are fitted with different
types of bearing. Bearings and lubrication appear from the table:
Pump Bearing
NKF 50-200
NKF 65-200
NKF 80-200
6306.2ZR.C3
NKF 80-250
NKF 150-400
NKF 150-500
NKF 200-500 6308.2ZR.C3
12.5.2 Motor bearings
Motors up to and including frame size 160 have maintenance-
free, greased-for-life bearings.
Motors of frame sizes above 160 should be greased according to
the indications on the motor nameplate. Grease spills from the
motor may occur.
For grease specifications, see section 12.5.3 Bearing grease.
12.5.3 Bearing grease
Use Lithium-based grease according to these specifications:
• 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.
Lubrication
Maintenance-free,
greased-for-life bearings.
Bearings to be greased via the
grease nipples of the pump.
Grease the bearings every 5000
operating hours.
Quantity of grease: 50 g.
See section 12.5.3 Bearing
grease

13. Periods of inactivity

During inactive periods, if the pump has not been test-run for a
long time and the water has been drained off, we recommend that
you turn the shaft by hand from time to time to prevent the pump
from seizing up.
Warning
Make sure that the escaping water does not
cause personal injury or damage to the motor or
other components.

14. Service

To place an order for service parts, please contact Grundfos.
Please inform us about the serial number of the pump unit and
describe the specific part to be replaced.
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