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14. Fault finding
WARNING
Electric shock
Death or serious personal injury
- Switch off the power supply for at least five
minutes before you start any work on the product.
- Make sure that the power supply cannot be
accidentally switched on.
Fault
Possible cause
1. The pumps are not
a) The actual pressure is higher than or
running.
b) The power supply has been switched off. Connect the power supply.
c) The main switch has cut out.
d) The main switch is defective.
e) The motor protection has been
f)
g) The pressure transmitter is defective.
h) The cable is broken or short-circuited.
2. The pumps start, but
a) Water shortage or no inlet pressure.
stop immediately. The
operating pressure is
not reached.
3. The booster system has
a) The pressure transmitter is defective.
stopped and cannot
restart.
b) The cable is broken or short-circuited.
c) The power supply to CU 323 has been
d) CU 323 is defective.
4. Unstable water supply
a) The inlet pressure is too low.
from the booster
b) The inlet pipe, strainer or pumps are
system.
c) The pumps suck air.
d) The pressure transmitter is defective.
5. The pumps are running,
a) The valves are closed.
but deliver no water.
b) The inlet pipe or pumps are blocked by
c) The non-return valve is blocked in the
d) The inlet pipe is leaky.
e) There is air in the inlet pipe or pumps.
6. The booster system is
a) The consumption is too high.
unable to reach the
setpoint.
b) Too many standby pumps have been
c) There is a pipe fracture or a leakage in
7. Leakage from the shaft
a) The shaft seal is defective.
seal.
8. Noise.
a) The pumps are cavitating.
9. Very frequent starts and
a) The diaphragm tank precharge pressure
stops.
18
equal to the setpoint.
activated.
The motor is defective.
switched off.
partly blocked by impurities.
impurities.
closed position.
selected.
the system.
is not correct.
Remedy
Wait until the pressure has dropped, or lower the pressure
on the outlet side of the booster system. Check that the
pumps start.
Cut in the main switch.
Replace the main switch.
Contact Grundfos.
Repair or replace the motor.
Replace the pressure transmitter.
0-145 psi (0-10 bar) transmitters with 0-10 V, 0-20 mA or
4-20 mA output signals are monitored by the booster
system.
Repair or replace the cable.
Re-establish the supply of water to the booster system.
When the inlet pressure has been re-established, press
[RESET] to restart the system.
Replace the pressure transmitter.
0-145 psi (0-10 bar) transmitters with 0-10 V, 0-20 mA or
4-20 mA output signals are monitored by the booster
system.
Repair or replace the cable.
Connect the power supply.
Contact Grundfos.
Check the inlet pipe and the inlet strainer, if any.
Clean the inlet pipe, strainer or pumps.
Check the inlet pipe for leakages.
Replace the transmitter.
Open the valves.
Clean the inlet pipe or pumps.
Clean the non-return valve. Check that the non-return valve
moves freely.
Check the inlet pipe for leakages.
Vent and prime the pumps. Check the inlet pipe for
leakages.
• Reduce the consumption, if possible.
• Install a bigger booster system.
Reduce the number of standby pumps.
Check the system, and repair the damaged parts, if
necessary.
Replace the shaft seal.
Clean the inlet pipe or pumps and possibly the inlet strainer.
Set the correct precharge pressure.
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