Problems: Causes And Remedies - Andritz SU8 Serie Instructions De Service

Series SU8

6. Problems: causes and remedies

Problem Cause
1. The pump does a) The fuses are blown.
not run.
b) The ELCB or the voltage-operated
ELCB has tripped out.
c) No electricity supply.
d) The motor starter overload has tripped
out.
e) Motor starter/contactor is defective.
f) Starter device is defective.
g) The control circuit has been inter-
rupted or is defective.
h) The dry-running protection has cut off
the electricity supply to the pump, due
to low water level.
i) The pump submersible drop cable is
defective.
2. The pump runs a) The discharge valve is closed.
but gives no
b) No water or too low water level in
water.
borehole.
c) The non-return valve is stuck in its shut
position.
d) The inlet strainer is chocked up.
e) The pump is defective.
3. The pump runs a) The drawdown is larger than anti-
at reduced cipated.
capacity.
b) Wrong direction of rotation.
c) The valves in the discharge pipe are
partly closed/blocked.
d) The discharge pipe is partly choked by
impurities (ochre).
e) The non-return valve of the pump is
partly blocked.
f) The pump and the riser pipe are partly
choked by impurities (ochre).
g) The pump is defective.
h) Leakage in the pipework.
i) The riser pipe is defective.
4. Frequent starts a) The differential of the pressure switch
and stops. between the start and stop pressures is
too small.
b) The water level electrodes or level
switches in the reservoir have not been
installed correctly.
c) The non-return valve is leaking or stuck
half-open.
26
Remedy
Replace the blown fuses. If the new ones blow too, the electric
installation and the submersible drop cable should be checked.
Cut in the circuit breaker.
Contact the electricity supply authorities.
Reset the motor starter overload (auto-matically or possibly
manually). If it trips out again, check the voltage. Is the voltage
OK, see items e) - h).
Replace the motor starter/contactor.
Repair/replace the starter device.
Check the electric installation.
Check the water level. If it is OK, check the water level
electrodes/level switch.
Repair/replace the pump/cable.
Open the valve.
See item 3 a).
Pull out the pump and clean or replace the valve.
Pull out the pump and clean the strainer.
Repair/replace the pump.
Increase the installation depth of the pump, throttle the pump or
replace it by a smaller model to obtain a smaller capacity.
Change direction of rotation.
Check and clean/replace the valves, if necessary.
Clean/replace the discharge pipe.
Pull out the pump and check/replace the valve.
Pull out the pump. Check and clean or replace the pump, if
necessary. Clean the pipes.
Repair/replace the pump.
Check and repair the pipework.
Replace the riser pipe.
Increase the differential. However, the stop pressure must not
exceed the operating pressure of the pressure tank, and the
start pressure should be high enough to ensure sufficient water
supply.
Adjust the intervals of the electrodes/ level switches to ensure
suitable time between the cutting-in and cutting-out of the
pump. See Installation and Operating Instructions for the
automatic devices used. If the intervals between stop/start
cannot be changed via the automatics, the pump capacity may
be reduced by throttling the discharge valve.
Pull out the pump and clean/replace the non-return valve.
Table 2: Problems