Diaphragm
–Liquid pump NF 10
Troubleshooting
KNF Flodos AG BA_NF10_EN_05_069219
Operating and Installation Manual
20
9. Troubleshooting
For pumps with alternating current motors:
GEFAHR
Life threat by electric shock
Before working on the pump separate the pump
from the power supply.
Ensure that the pump is de-energised.
Pump does not pump
Possible cause
Corrective action
Pump not connected to mains
power supply.
Connect pump to mains supply.
Power supply is not switched
on.
Switch on power supply.
Connections or tubing are
blocked
Check tubing lines and connections.
Remove blockage.
External valve is closed or filter
is blocked.
Check valve timing and filters.
Diaphragm or valves are worn
out.
Replace diaphragm and valves
(See paragraph 8.3).
Tab. 16
Pump is not priming / sucking
Possible cause
Corrective action
Pump is not connected suction
side.
Check the arrows on the pump head indicating flow
direction.
Liquid in the container is too
low.
Fill container.
Hose connections are not tight.
Check for tightness
– use clamp to ensure a good fit.
System valve is closed or filter
is blocked.
Open the valve.
Clean / replace filter.
The vacuum is too small for the
suction height.
Reduce suction height.
Valves are blocked by particles
Clean the pump head (see section 8.2).
Pump head materials are not
resistant to the liquids being
pumped.
Check compatibility lists and choose suitable version.
Inlet and outlet tubes have been
wrongly connected.
Check the arrows on the pump head indicating flow
direction
Tab. 17
