The pump starts up but does not deliver liquid
• Pump is not primed = repeat the "pump
priming" procedure
• The pump takes in air = check the
liquid level, operation of the foot valve
and the suction pipeline
Pump performance is reduced
• Pipelines obstructed = check pipelines
Pump performance is unstable
• Pump suction pressure too low or
cavitation = check the pump inlet
conditions
• Suction pipe is partially obstructed
with impurities = clean the suction pipe
The pump rotates in the opposite direction when shut down
• Foot valve or check valve defective or
blocked in the open position = remove
and clean or replace the valves
• The foot valve is blocked in the closed
position = replace or clean the valve
• The electronic device is blocked = the
pump has problems with suction (dry
run protection tripped)
• Pump is not primed correctly = repeat
the "pump priming" procedure
• Leak from suction pipe = repair or
replace suction pipe
• air in suction pipe = bleed the suction
pipe, repeat the "pump priming"
instructions
• Leak from suction pipe = remove and
repair suction pipe
• For selfpriming pumps only: The liquid
column above the check valve on the
delivery pipeline prevents selfpriming
of the pump = drain the delivery
pipeline Check that check valve does
not retain liquid in the delivery pipeline
Repeat the startup procedure.
• For selfpriming pumps only: the
internal valve has not closed =
gradually close a valve until there is
a visible increase in pressure or flow.
Then open the valve gradually until the
required flow rate is reached.
• The pump only operates intermittently
= loss from system below minimum
flow of electronic control device
• For selfpriming pumps only: The
differential pressure inside the pump
is too low = gradually close a valve until
delivery pressure stabilizes and the
noise level is reduced
EN
21