Fault Finding - Grundfos Hydro Multi-E Series Installation And Operating Instructions Manual

24. Fault finding

WARNING
Electric shock
Death or serious personal injury
- Switch off the power supply and wait at least five
minutes before you start any work on the product.
Make sure that the power supply cannot be
accidentally switched on.
Fault
1. Hydro Multi-E does not run
when started.
2. Hydro Multi-E starts, but
stops immediately
afterwards. The operating
pressure is not reached.
3. Hydro Multi-E is stopped
and cannot restart.
4. Unstable water supply
from Hydro Multi-E (only
applies to very low
consumption).
5. Pumps are running, but
deliver no water.
6. Hydro Multi-E is unable to
reach the setpoint.
7. Leakage from a shaft seal. a) The shaft seal is defective.
8. Noise.
9. Very frequent starts and
stops.
Cause
a) The actual pressure is higher than or
equal to the setpoint set.
b) The power supply is disconnected.
c) The circuit breakers have cut out.
d) The internal motor protection is activated. Contact Grundfos.
e) The circuit breaker is defective.
f) The motor is defective.
g) Outlet-pressure sensor fault.
– The outlet-pressure sensor is defective.
– The cable is broken or short-circuited.
a) Dry running or no inlet pressure.
a) Outlet-pressure sensor fault.
– The outlet-pressure sensor is defective.
– The cable is broken or short-circuited.
b) Terminal box unit fault.
– The power supply is disconnected on
pump 1.
– The terminal box is defective.
a) The inlet pressure is too low.
b) The inlet pipe or pumps are partly blocked
by impurities.
c) The pumps suck air.
d) The outlet-pressure sensor is defective.
a) The inlet pipe or pumps are blocked by
impurities.
b) The non-return valve is blocked in the
closed position.
c) The inlet pipe is leaky.
d) Air in inlet pipe or pumps.
a) The cable is broken or short-circuited
(GENIbus communication between pump
1 and pump 2/3).
b) Pump 2 or 3 is out of operation.
b) CRE and CRIE pumps:
The height adjustment of the pump shaft
is inaccurate.
a) The pumps are cavitating.
b) CRE and CRIE pumps:
The pumps do not rotate freely (frictional
resistance) due to inaccurate height
adjustment of the pump shaft.
a) Wrong diaphragm tank precharge
pressure.
b) The difference between start and stop
pressures is too small.
Note: This situation will only arise if
emergency operation is installed.
WARNING
Crushing of feet
Death or serious personal injury
- Use appropriate tools and lifting equipment when
dismantling the product.
Remedy
Wait until the pressure has dropped, or lower the
pressure on the outlet side of Hydro Multi-E, and check
that the booster system starts.
Connect the power supply.
Correct the fault and cut in the circuit breakers.
Replace the circuit breaker.
Repair or replace the motor.
Replace the outlet-pressure sensor.
Repair or replace the cable.
Check the supply of water to Hydro Multi-E. When the
inlet pressure has been re-established, the pumps will
restart after 15 seconds.
Replace the outlet-pressure sensor. Outlet-pressure
sensors with 0-20 mA or 4-20 mA output signals are
monitored by Hydro Multi-E.
Repair or replace the cable.
Connect the power supply.
Replace the terminal box of pump 1.
Contact Grundfos.
Check the inlet pipe and possible inlet strainer.
Clean the inlet pipe or pumps.
Check the inlet pipe for leakages.
Replace the outlet-pressure sensor.
Clean the inlet pipe or pumps.
Clean the non-return valve. The non-return valve must
move freely.
Check the inlet pipe for leakages.
Vent the pumps. Check the inlet pipe for leakages.
Repair or replace the cable.
Connect the power supply to the pump and check the
pump condition.
Replace the shaft seal.
Re-adjust the shaft height.
Clean the inlet pipe or pumps and possibly the inlet
strainer.
Re-adjust the shaft height. See the CR, CRI, CRN
installation and operating instructions supplied with
Hydro Multi-E.
Check the precharge pressure.
Increase the differential pressure setting on each
pressure switch.
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