Fault Finding Chart - Grundfos Fire NKF Montage- Und Betriebsanleitung

10. Fault finding chart

Warning
Before any servicing of the pump, make sure that the pump unit cannot accidentally start.
Fault Cause
1. Pump delivers no or a) Air in suction pipe.
too little water.
b) Pump draws in air due to defective gaskets.
c) Counter-pressure too high.
d) Inlet pressure too low.
e) Suction pipe or impeller blocked.
2. Pump makes a) Inlet pressure too low (cavitation).
strange noises and/
or runs unevenly.
b) Air in suction pipe.
c) Impeller off-balance.
d) Inner parts worn.
e) Pump stressed by the pipework.
f)
g) Defective coupling.
h) Foreign bodies in the pump.
3. Leakage in pump a) Pump stressed by the pipework.
housing.
b) Pump housing gaskets or gasket at
4. Leakage in the shaft a) Mechanical shaft seal dirty or stuck together.
seal.
b) Mechanical shaft seal defective.
c) Shaft surface or shaft sleeve defective.
5. Too high pump a) Air in the pump.
temperature.
b) Inlet pressure too low.
c) Bearings lubricated with too little, too much or
d) Pump with bearing seat stressed by pipework. Mount the pump so that it is not stressed. Support the
e) Axial pressure too high.
6. Engine does not a) Fuel tap closed.
start.
b) No diesel in the tank.
c) Fuel filter blocked.
d) Air in fuel system.
e) Water in the fuel.
f)
g) Insufficient power supply.
h) Exhaust pipes blocked.
7. Oil pressure is too a) Oil filter blocked.
high or too low when
b) Water or fuel in the oil.
engine is running.
c) Oil level too low/too high.
d) Oil pump worn.
Defective bearings.
connections defective.
unsuitable lubricant.
Starter relay defective.
Remedy
Fill storage container with water. Vent pump. Make sure
the suction pipe has been installed according to section
5.1.4 Pipework
Check the pipeline gaskets and pump housing gaskets,
and replace if necessary.
Check the system for impurities and blockages.
Make sure that the storage tank is filled with enough
water and that the conditions in section 4.5.1 Minimum
inlet pressure are complied with.
Clean suction pipe and pump.
Make sure that the storage tank is filled with enough
water and that the conditions in section 4.5.1 Minimum
inlet pressure are complied with.
Refill the storage tank with water. Vent pump. Make sure
the suction pipe has been installed according to section
5.1.4 Pipework
Clean the impeller and remove foreign particles.
Replace defective parts.
Mount the pump so that it is not stressed. Support the
pipes.
Replace bearings.
Replace coupling.
Clean the pump and remove foreign bodies.
Mount the pump so that it is not stressed. Support the
pipes.
Replace defective gaskets.
Check and clean the mechanical shaft seal.
Replace the mechanical shaft seal.
Replace the shaft or the shaft sleeve.
Fill the storage tank with water. Vent pump.
Make sure that the storage tank contains enough water
and that all conditions in section 4.5.1 Minimum inlet
pressure are complied with.
Replenish, reduce or replace the lubricant.
pipes. Check the alignment of the pump, and correct, if
necessary. See section 5.1.9 Aligning pump and engine.
Check the relief holes of the impeller and the lock rings
on the suction side.
Open fuel tap on the diesel tank.
Re-fill tank with diesel. Vent fuel system. See sections
9.3.3 Fuel system and 9.5 Changing the fuel filter.
Change fuel filter. See section 9.5 Changing the fuel
filter.
Vent fuel system.
Drain fuel from the fuel tank. Re-fill with new fuel.
Vent fuel system.
Replace starter relay.
Check power supply to the control cabinet, batteries and
cables on the pump unit.
Remove foreign bodies from exhaust pipes.
Replace oil filter. See section 9.4 Oil change with filter.
Change oil. See section 9.4 Oil change with filter.
Refill oil. See section 9.3.1 Oil level. Drain oil.
See section 9.4 Oil change with filter.
Replace oil pump.
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