English (GB)
8
13. Fault finding
14. Service documentation
Service documentation is available in Grundfos Product Center:
http://product-selection.grundfos.com/.
If you have any questions, please contact the nearest Grundfos
company or service workshop.
Warning
Before removing the terminal box cover and before
removing/dismantling the module, make sure that the
power supply has been switched off and that it
cannot be accidentally switched on.
Fault
Cause
Remedy
1. The booster system
stops occasionally.
One or more
modules stop.
a) No or insufficient water supply. The
pressure switch has cut out.
Check that the pressure switch functions normally (without
delay) and is adjusted correctly. Check that the minimum
inlet pressure is correct.
b) The capacity is too small. The flow switch
has cut out.
The discharge pipe is totally or partly blocked due to
incorrectly adjusted manually operated valve or failure in
the magnetic or motor-operated valve.
Check these valves.
The flow switch is faulty or incorrectly adjusted.
Check/adjust the switch.
2. The booster system
does not run.
a) The fuses are blown.
Check and replace both main fuses and/or fuses for control
circuit.
b) The motor-protective circuit breaker has
tripped.
Reset the motor-protective circuit breaker. If it trips again,
the voltage should be checked.
c) The magnetic coil of motor-protective
circuit breaker/contactor is short-circuited
(not cutting in).
Replace the coil. Check the coil voltage.
d) The control circuit has cut out or is
defective.
Check the control circuit and the contacts in the monitoring
devices (pressure switch, flow switch, etc.).
e) The motor/supply cable is defective.
Check motor and cable. See also section
3. The booster system
runs, but gives no
water or develops no
pressure.
a) No water or too small quantity delivered to
the modules or air in the system.
Check that the inlet pressure during operation is at least 0.5
bar for BM 4" and BM/BMhp 6", and 1 bar for BM/BMhp 8".
If this is the case, the water supply is OK. Stop and vent the
system. Restart the system as described in section
If the module is defective, it should be dismantled and
repaired or replaced.
b) Suction parts are blocked.
Pull the pump out of the sleeve, and clean the suction parts.
4. The booster system
runs at reduced
capacity (flow and
pressure).
a) Wrong direction of rotation.
See section
9. Before starting the booster module(s)
b) The valves on the discharge side are partly
closed or blocked.
Check valves.
c) The discharge pipe is partly blocked by
impurities.
Measure the discharge pressure and compare with the
calculated data. Clean or replace the discharge pipe.
d) The module is partly blocked by impurities. Pull the pump out of the sleeve. Dismantle, clean and check
the pump. Replace defective parts. Clean the pipes.
e) The module is defective.
Pull the pump out of the sleeve. Dismantle, clean and check
the pump. Replace defective parts. See section
