Diaphragm liquid pump NF 25, NFB 25
Troubleshooting
KNF Flodos AG BA_NF25_NFB25_EN_07_159615
Translated from the Original Operating and Installation Instructions
22
9. Troubleshooting
Disconnect the pump from the power supply before working on
the pump.
Make sure that the pump is de-energised.
Pump does not work
Possible cause
Remedy
Pump not connected to power
supply
Connect pump to power supply
Power supply is not switched on
Switch on power supply
Thermal switch or pump elec-
tronics have tripped
Disconnect pump from the mains
Allow pump to cool
Identify and eliminate cause of overheating/overload
Connections or hoses are
blocked
Check connections and hoses
Remove blockage
External valve is closed or filter
is clogged
Check external valves and filters
Diaphragm, anchor valves or
seals are worn.
Replace diaphragm, anchor valves and seals
(see Chapter 8.3)
Tab. 13
Pump is not priming
Possible cause
Remedy
Suction side of pump not con-
nected
Connect the suction side of the pump
Liquid in the container is too low
Fill container
Hose connections are not leak-
tight
Secure transition joints between hose and connections with
clamps or other clamping elements
Peripheral valve is closed or
filter is clogged
Open the peripheral valve
Clean filter
Pump head is filled with gas.
The system is unable to handle
the pressure on the pressure
side
Reduce pressure at pressure side
Particles in the pump
Clean the pump head (see Chapter 8.2)
The pump parts are not re-
sistant to the medium to be
transferred
Replace the pump head with a compatible version
Incorrect interchange of pres-
sure and suction line connec-
tions
Remove pressure and suction lines and reconnect correctly
Tab. 14
