Fault Finding - Grundfos BME Montage- Und Betriebsanleitung

21. Fault finding

Warning
Before starting work on the booster module, make sure that the power supply has been switched off and that it
cannot be accidentally switched on.
Fault Possible cause
1. The booster module a) No water supply.
starts/stops
occasionally during
operation.
b) The lubricating oil level is too low.
2. The booster module a) The fuses are blown.
stops during operation.
b) The motor starter overload unit has tripped.
c) The magnetic coil of motor starter/contactor
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 booster module a) No or insufficient water supply at the module
runs, but gives no
water or develops any
pressure.
b) The piping system, pump or nozzle is
c) The pre-filter is choked up.
4. The booster module a) Wrong direction of rotation.
runs at 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)
16
The low-pressure switch has cut out.
is defective (not cutting in).
inlet.
choked up.
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 feed pump. See
section 8. Startup.
Check that the oil level switch functions normally. If it is
OK, check the oil system for leakage. See section
16. Oil lubrication system.
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
5. Electrical connection, 6. Motor protection
7. Before starting the booster module.
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 for BME and 2 bar for BMET. See sections
8.1 BME and 8.2 BMET.
Restart the booster module as described in section
8. Startup.
Check the function of the feed pump.
Check the piping system, pump and nozzle.
Clean the pre-filter.
See section 9. Liquid filling, venting and checking of
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 and module. Replace any defective
parts.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump and module. Replace any defective
parts.
Clean the pre-filter.
and
6.2 Setting of