English (GB)
35
Dosing flow too
small.
Suction valve: During the discharge
stroke, the dosing liquid flows back
into the suction line.
Discharge valve: During the suction
stroke, the dosing liquid flows back
into the dosing head.
The pump takes in less.
Suction/discharge valves dirty or leaky. Clean or replace valves.
Dosing flow depends very much on
the pressure.
If the counter-pressure 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 the piston and piston slide
valves. Use other hydraulic oil with
a higher viscosity (mainly for
frequency converter operation and
higher counter-pressures).
Pressure gauge in discharge line.
Counter-pressure has seriously
increased. Overpressure valve is
adjusted too low.
Readjust the zero point.
Correct the setting of the pressure
relief valve.
Especially at stroke frequencies
below 15 strokes/min., e.g.
frequency converter operation.
Degassing valve (M) is not working
properly.
Replace the degassing valve (M) or,
if necessary, replace with
∅
8 ball.
Pump doses too
much.
Pressure gauge in discharge line.
Counter-pressure has seriously
dropped.
Readjust the zero point.
Heavy overdose.
Inlet pressure of suction line higher
than counter-pressure of discharge
line.
Install a pressure-loading valve.
Overdosing at high dosing flow
settings and flows.
Too big dynamic in the suction line.
Install a pulsation damper on the
suction side.
Fault
Diagnosis
Cause
Remedy
