Fault Finding Chart; Company Or Service Workshop - Grundfos DDI 222 Instrucciones De Instalación Y Funcionamiento

11. Fault finding chart

Fault Cause
1. Dosing pump does a) Not connected to the mains.
not run.
b) Incorrect mains voltage.
c) Electrical failure.
2. Pump does not suck a) Crystalline deposits in the valves.
in or dose.
b) Empty dosing tank.
c) Air in the suction line and dosing head.
d) Valves not correctly assembled.
3. Dosing pump does a) Leaking suction line.
not suck in.
b) Cross-section of the suction line too small or
c) Clogged suction line.
d) Foot valve covered by sediment.
e) Buckled suction line.
f)
g) Diaphragm broken or diaphragm tappet torn out. Replace the diaphragm.
h) Excess counter-pressure.
i)
4. Dosing pump does a) Viscosity or density of medium too high.
not dose.
b) Crystalline deposits in the valves.
c) Valves not correctly assembled.
d) Injection unit blocked.
e) Incorrect installation of lines and peripheral
f)
g) Sealing elements not chemically resistant.
5. Dosing flow of the a) Degassing medium.
pump is inaccurate.
b) Parts of the valves covered in dirt or incrusted.
c) Incorrect dosing flow display.
d) Counter-pressure fluctuations.
e) Suction lift fluctuations.
f)
g) Leaking or porous suction line or discharge line. Replace the suction line or discharge line.
h) Parts in contact with the medium are not
i)
j)
k) Overflow.
6. Liquid leaks out of a) A diaphragm leakage has occurred.
the hole in the
intermediate flange
between the pump
and the dosing head.
For further error signals for the control unit, refer to
Note
the relevant section.
suction line too long.
Crystalline deposits in the valves.
Empty dosing tank.
equipment.
Empty dosing tank.
Siphon effect (inlet pressure higher than
counter-pressure).
resistant to it.
Dosing diaphragm worn (incipient tears).
Variation of the dosing medium (density,
viscosity).
Remedy
Connect the power supply cable.
Switch off the pump. Check voltage and motor. If the
motor is faulty, return the pump for repair.
Return the pump for repair.
Clean the valves.
Fill dosing tank.
Fill dosing head and suction line.
Assemble the valve inner parts in the right order and
check or possibly correct the flow direction.
Replace or seal the suction line.
Check with Grundfos specification.
Rinse or replace the suction line.
Suspend the suction line from a higher position.
Install the suction line correctly. Check for damage.
Clean the valves.
Depressurise the system on the discharge side of the
pump.
Fill the dosing tank.
Check the installation.
Clean the valves.
Assemble the inner valve parts in the right order and
check or possibly correct the flow direction.
Check and possibly correct the flow direction, or
remove the obstruction.
Check the lines for free passage and correct
installation.
Fill the dosing tank.
Replace sealing elements.
Check the installation.
Clean the valves.
Calibrate.
Install a pressure-loading valve and a pulsation
damper, if necessary.
Keep the suction level constant.
Install a pressure-loading valve.
Replace with resistant materials.
Replace the diaphragm. Also observe the
maintenance instructions.
Check the concentration. Use an agitator, if necessary.
Install or check suction and pressure pulsation
damper, recalculate installation, install a
pressure-loading valve.
Replace the diaphragm.
12. Disposal
This product or parts of it must be disposed of in an
environmentally sound way. Use appropriate waste collection
services. If this is not possible, contact the nearest Grundfos

company or service workshop.

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