Grundfos Fire DNF, Инструкция по установке и эксплуатации

Страница: 26 / 36

English (GB)
26
15. Fault finding
Warning
Before carrying out any service of the pump, make sure that the fire pump set cannot accidentally start.
Fault Cause Remedy
1. Pump delivers no or too
little water.
a) Wrong direction of rotation. Interchange two phases of the power supply.
b) Air in suction pipe. Fill storage container with water. Make sure the
suction pipe has been installed according to
section
9.5 Pipework
.
c) Pump draws in air due to defective gaskets. Check the pipeline gaskets and pump housing
gaskets, and replace if necessary.
d) Counter-pressure too high. Check the system for impurities and blockages.
e) Inlet pressure too low. Make sure that the storage tank is filled with
enough water, and that the conditions in section
8.1 Minimum inlet pressure
are complied with.
Open the isolating valve on the suction side
completely.
f) Suction pipe or impeller blocked. Clean suction pipe and pump.
2. Pump is noisy and/or
runs unevenly.
a) Inlet pressure too low (cavitation). Make sure that the storage tank is filled with
enough water and that the conditions in section
8.1 Minimum inlet pressure
are complied with.
Open the isolating valve on the suction side
completely.
b) Air in suction pipe or pump. Refill the storage tank with water. Vent pump.
Make sure the suction pipe has been installed
according to section
9.5 Pipework
.
c) Impeller out of balance. Clean the impeller.
d) Inner pump parts worn. Replace defective parts.
e) Pump stressed by the pipework. Install the pump so that it is not stressed.
Support the pipes.
f) Defective bearings. Replace bearings.
g) Defective coupling. Replace coupling.
h) Foreign bodies in the pump. Clean the pump and remove foreign bodies.
3. Leakage from pump. a) Pump stressed by the pipework. Install the pump so that it is not stressed.
Support the pipes.
b) Pump housing gaskets or pipe gaskets defective. Replace defective gaskets.
4. Excessive leakage from
stuffing box.
a) Stuffing box packing too loose. Tighten the gland bolts evenly to obtain a
leakage of 40 60 drops per minute.
b) Stuffing box packing worn. Replace stuffing box packing. See service
instructions.
5. Too high pump
temperature.
a) Air in the pump. Fill the storage tank with water.
b) Inlet pressure too low. Make sure that the storage tank contains
enough water and that all conditions in section
8.1 Minimum inlet pressure
are complied with.
c) Bearings lubricated with too little, too much or
unsuitable lubricant.
Replenish, reduce or replace the lubricant.
d) Pump with bearing seat stressed by pipework. Install the pump so that it is not stressed.
Support the pipes. Check the alignment of the
pump, and correct, if necessary. See section
9.9 Alignment
.
e) Axial pressure too high. Check the relief holes of the impeller and the
lock rings on the suction side.