Grundfos POMONA PO07, Installation And Operating Instructions Manual

Page: 10 / 104

English (GB)
10
13. Fault finding
* Contact the manufacturer.
Warning
Before removing the terminal box cover and carrying
out any work on the pump, make sure that the power
supply has been switched of and that it cannot be
accidentally switched on. Drain the pump.
Fault Cause Remedy
1. Pump does not pump,
pump performance is
poor, or pump does
not suck.
a) Incorrect electrical connection. Check the electrical connection and correct,
if necessary.
b) Incorrect direction of rotation. Interchange two phases.
c) Too little liquid in the pump housing. Vent and fill the suction pipe and pump.
d) Air cannot escape. Discharge pipe clogged. Open all valves.
e) Suction head too large.* Increase the liquid level on the suction side.
Open the isolating valve on the suction side.
f) Pipes clogged or foreign body in the impeller. Open the pump and remove blockage.
g) Air sucked in through a defective seal. Inspect pipe seals, pump housing seals and shaft
seals. Replace defective seals.
h) Pump sucks air because of too little liquid. Increase the liquid level on the suction side and keep it
as constant as possible.
2. Motor-protective
circuit breaker trips.
Motor is overloaded.
a) Pump blocked. Open the pump and remove the blockage.
b) Pump cannot run as the pump housing is
stressed by the pipework.
Install the pump so that it is not stressed by the
pipework. Support the pipes.
c) The density or viscosity of the pumped liquid
is higher than that stated in the order.*
If a lower performance than that given is sufficient,
throttle the flow on the suction side. If not, use a larger
motor.
d) Motor-protective circuit breaker not correctly
set.
Check the setting. Replace the motor-protective circuit
breaker, if defective.
e) Motor running on two phases of three-phase
supply.
Check the electrical connection. Replace the fuse,
if defective.
3. Pump too noisy.
Pump does not run
smoothly and vibrates.
a) Suction head too large.* Increase the liquid level on the suction side.
Completely open the isolating valve on the suction side.
b) Air in the suction pipe or pump. Vent and fill the suction pipe and pump.
c) Pump sucks air because of too little liquid. Increase the liquid level on the suction side and keep it
as constant as possible.
d) Impeller is out of balance
(clogged impeller blades).
Clean and check the impeller.
e) Internal parts are worn. Replace defective parts.
f) Pump stressed by the pipework
(causing starting noise). Install the pump so that it is not stressed by the
pipework. Support the pipes.
g) Defective bearings. Replace bearings.
h) Bearings greased with too little, too much or
wrong type of grease.
Add, remove or replace grease.
i) Motor fan defective. Replace the fan.
j) Rubber element of coupling (power
transmission) defective. Replace the rubber element and realign the coupling.
See section
8.3 Aligning versions with bearing bracket .
k) Foreign body in the pump. Open and clean the pump.
4. Pump or connections
leaking. Shaft seal or
stuffing box is leaking.
a) Pump is stressed by the pipework (causing
leaking pump housing or connections).
Install the pump so that it is not stressed. Support the
pipes.
b) Housing seal and connection seals defective. Replace seals.
c) Shaft seal dirty or stuck. Check and clean the seal.
d) Shaft seal worn. Replace the seal.
5. Overtemperature of
pump, bearing bracket
or motor.
a) Air in the suction pipe or pump. Vent and fill the suction pipe and pump.
b) Suction head too large. Increase the liquid level on the suction side.
Open the isolating valve on the suction side.
c) Bearings greased with too little, too much or
wrong type of grease.
Add, remove or replace grease.
d) Pump with bearing bracket is stressed by the
pipework.
Install the pump so that it is not stressed. Support the
pipes. Check the alignment of the coupling.
e) Motor-protective circuit breaker defective or
not correctly set.
Check the setting. Replace the motor-protective circuit
breaker, if necessary.