KM 254 en
46
15.720039-V1.0
Dosing flow too small
Suction valve: during the pressure
stroke the dosing liquid flows back
into the suction line.
Pressure valve: during the suction
stroke, the dosing liquid flows back
into the dosing head; the pump
takes in less.
Suction/pressure valves dirty
or leaky.
Clean or exchange valves.
Dosing flow depends very much
on the pressure; if the
backpressure is low, the dosing
flow increases considerably. If the
stroke frequency rises, the dosing
flow increases excessively.
Too much clearance between
piston and slide valve, or the
stroke frequency of the pump
is too low (too much slip).
Replace piston and piston slide
valves, use anderes other
hydraulic oil with a higher
viscosity, (mainly for frequency
controller operation and higher
backpressures).
Manometer pressure line.
Backpressure has seriously
increased; overpressure valve
is adjusted too low.
Readjust zeropoint.
Correct setting of the pressure
relief valve.
Especially with stroke frequencies
below 15H/min, e.g. with
frequency converter operation.
Degassing valve (M) is not
working properly.
Replace degassing valve (M), or if
necessary replace with ø8 ball.
Pump doses too much
Manometer pressure line
Backpressure has seriously
dropped.
Readjust zeropoint.
Heavy overdose
Admission pressure of suction
line > backpressure of
pressure line.
Install a pressure retention valve.
Overdosing at bigger dosing flow
adjustments and flows.
Too big dynamic in the suction
line.
Mount a suction pulsation damper.
Fault
Diagnosis
Cause
Remedy