Neptune NXP-M Operating Instructions Manual page 37

Stepper motor-driven diaphragm dosing pump NXP-M and NXP-P
Possible cause
Viscosity too high.
Current supply interrupted.
Dry the valves.
Air in the suction line with
simultaneous pressure on the
discharge valve.
Table 31: Type of fault: Dosing pump does not prime
13.1.4 Delivery rate varies
Possible cause
Valve leaking or blocked.
Valve damaged (e.g. valve
balls).
Suction line is leaking.
Suction line is blocked (e.g.
screen in foot valve).
Viscosity too high.
The dosing pump's electrical
data does not match that of
the mains supply.
Suction side pressure too high
(pump siphoning).
Pressure peaks due to
acceleration with long suction
lines.
Table 32: Type of fault: Delivery rate varies
Subject to technical changes.
Remedy
è
Possibly reduce the concentration
of the dosing medium or increase
the temperature.
è
Install spring-loaded valves.
è
Increase the pipe diameter.
è Reconnect the current supply.
è
Dampen the dosing head and the
valves
è
Vent the dosing head.
è
Vent the dosing head or the lines.
Remedy
è
Clean the valve and vent the
dosing pump.
è
Tighten the screw connections.
è
Remove the damaged parts or
install a new valve.
è
Seal the leak locations or replace
the parts.
è
Clean the suction line.
è
Possibly reduce the concentration
of the dosing medium or increase
the temperature.
è
Install spring-loaded valves.
è
Increase the pipe diameter.
è
Check the electrical installation.
è
Install a back-pressure valve in
the pressure line.
è
Install a suction pressure
regulator.
Possible cause
Imprecise dosing due to
changeable positive and
negative suction heads.
System backpressure too
high (measured at discharge
connection of dosing pump).
Table 32: Type of fault: Delivery rate varies
13.1.5 No stroke movement observed
Possible cause
Diaphragm return spring
broken.
Current supply interrupted.
The dosing pump's electrical
data does not match that of
the mains supply.
Pressure peaks due to
acceleration with long suction
lines.
System backpressure too
high (measured at discharge
connection of dosing pump).
Table 33: Type of fault: No stroke movement observed
13.1.6 Dosing pump delivery rate too high
Possible cause
Suction side pressure too high
(pump siphoning).
Pressure peaks due to
acceleration with long suction
lines.
Table 34: Type of fault: Dosing pump delivery rate too high
Operating instructions
Remedy
è Install a suction pressure
regulator.
è
Clean blocked injection nozzle.
è
Install pulsation dampeners to
reduce pressure peaks if pipes
are too long.
è Check function of safety valves.
Remedy
è
Contact the manufacturer.
è
Reconnect the current supply.
è Check the electrical installation.
è
Install a suction pressure
regulator.
è
Clean blocked injection nozzle.
è
Install pulsation dampeners to
reduce pressure peaks if pipes
are too long.
è
Check function of safety valves.
Remedy
è Install a back-pressure valve in
the pressure line.
è
Install a suction pressure
regulator.
Troubleshooting
Type of fault
37