Fault Finding; Bme Hp Feed Pump - Grundfos BMEX Series Montage- Und Betriebsanleitung

22. Fault finding

22.1 BME hp feed pump

Warning
Before starting work on the BME hp feed pump,
make sure that the power supply has been switched
off and that it cannot be accidentally switched on.
Fault Possible cause
1. The pump starts/stops a) No water supply.
occasionally during
operation.
b) The lubricating oil level is too low.
2. The pump stops during a) The fuses are blown.
operation.
b) The motor starter overload unit has tripped.
c) The magnetic coil of the motor starter/
d) The control circuit has cut out or is defective. Check the control circuit and the contacts in the
e) The motor/supply cable is defective.
3. The pump runs, but a) No or insufficient water supply at the pump
gives no water nor
develops any pressure.
b) The piping system or the pump is choked up. Check the piping system and the pump.
c) The pre-filter is choked up.
4. The pump runs at a) Wrong direction of rotation.
reduced capacity.
b) The valves on the discharge side are partly
c) The discharge pipe is partly blocked by
d) The pump is partly blocked by impurities.
e) The pump is defective.
f)
The low-pressure switch has cut out.
contactor is defective (not cutting in).
inlet.
closed or blocked.
impurities.
The pre-filter is choked up.
Remedy
Check that the low-pressure switch functions normally
and is adjusted correctly. Check that the minimum inlet
pressure is correct. If not, check the sea-water feed
pump. See section 9. Startup and
Check that the oil level switch functions normally.
If it is OK, check the oil system for leakage. See section
17. Oil lubrication system, BME hp feed
After a cut-out, the cause of a possible short-circuit
must be found.
If the fuses are blown, check whether the motor starter
has been set correctly or is faulty.
If the fuses are hot when they are replaced, check that
the load of the individual phases does not exceed the
motor current during operation. Identify the cause of the
load.
If the fuses are not hot immediately after the cut-out, the
cause of a possible short-circuit must be identified.
Possible fuses in the control circuit must be checked,
and defective fuses must be replaced.
Reset the starter overload. See also sections
7. Electrical connection, 7.1.1 Motor protection
8. Before starting the BMEX.
Replace the coil. Check the coil voltage.
monitoring devices (low-pressure switch, flow switch,
etc.).
Check motor and cable. See section
motor starter.
Check that the inlet pressure during operation is at least
1 bar. See section 5.1 BME hp feed
Restart the pump as described in section
operation.
Check the function of the sea-water feed pump.
Clean the pre-filter.
See section 9.9 Liquid filling, venting and checking
direction of rotation.
Check the valves.
Clean or replace the discharge pipe. Measure the
discharge pressure, and compare the value with the
calculated data. See "Technical specification", supplied
with the system.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
Clean the pre-filter.
operation.
pump.
and
7.2.3 Setting of
pump.
9. Startup and
21