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11. Fault finding chart
Fault
Cause
Remedy
1.
Dosing pump does
not run.
a)
Not connected to the mains.
Connect the power supply cable.
b)
Incorrect mains voltage.
Switch off the pump. Check voltage and
motor. If the motor is faulty, return the
pump for repair.
c)
Electrical failure.
Return the pump for repair.
2.
Dosing pump does
not suck in.
a)
Leaking suction line.
Replace or seal the suction line.
b)
Cross-section of the suction line too
small or suction line too long.
Check with Grundfos specification.
c)
Clogged suction line.
Rinse or replace the suction line.
d)
Foot valve covered by sediment.
Suspend the suction line from a higher
position.
e)
Buckled suction line.
Install the suction line correctly.
Check for damage.
f)
Crystalline deposits in the valves.
Clean the valves.
g)
Diaphragm broken or diaphragm
tappet torn out.
Replace the diaphragm.
h)
Empty dosing tank.
Fill the dosing tank.
3.
Dosing pump does
not dose.
a)
Air in the suction line and dosing
head.
Fill the dosing head and suction line.
b)
Viscosity or density of medium too
high.
Check the installation.
c)
Crystalline deposits in the valves.
Clean the valves.
d)
Valves not correctly assembled.
Assemble the inner valve parts in the
right order and check or possibly correct
the flow direction.
e)
Injection unit blocked.
Check and possibly correct the flow
direction, or remove the obstruction.
f)
Incorrect installation of lines and
peripheral equipment.
Check the lines for free passage and
correct installation.
g)
Empty dosing tank.
Fill the dosing tank.
h)
Sealing elements not chemically
resistant.
Replace sealing elements.
