List Of Faults; Disposal - Grundfos DDE series Montage- Und Betriebsanleitung

8.2 List of faults

Fault
Dosing flow too high
No dosing flow or
dosing flow too low
Irregular dosing
Liquid escaping from
the drain opening on
the flange
Liquid escaping
Pump not sucking in

9. 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.
Possible cause
Inlet pressure greater than
backpressure
Air in dosing head
Faulty diaphragm
Leakage/fracture in lines
Valves leaking or blocked
Valves installed incorrectly
Blocked suction line
Suction lift too high
Viscosity too high
Deaeration valve open
Valves leaking or blocked
Backpressure fluctuations
Faulty diaphragm
Dosing head screws not
tightened
Valves not tightened
Suction lift too high
Backpressure too high
Soiled valves
Subject to alterations.
Possible remedy
Install additional spring-loaded valve
(approx. 3 bar) on the discharge side.
Increase pressure differential.
Deaerate the pump.
Change the diaphragm
(see section 7.3 Perform
Check and repair lines.
Check and clean valves.
Check that the arrow on the valve housing is
pointing in the direction of flow. Check whether all
O-rings are installed correctly.
Clean suction line/install filter.
Reduce suction lift.
Install priming aid.
Use hose with larger diameter.
Install spring-loaded valve on the discharge side.
Close the deaeration valve.
Tighten up valves, replace valves if necessary
(see section 7.3 Perform
Keep backpressure constant.
Immediately separate the pump from the power
supply!
Observe section 7. Service
7.4 Diaphragm breakage.
Tighten up screws
(see section 4.2 Hydraulic
Tighten up valves/union nuts
(see section 4.2 Hydraulic
Reduce suction lift; if necessary, provide positive
inlet pressure.
Open the deaeration valve.
Flush system, replace valves if necessary
(see section 7.3 Perform
service).
service).
and especially section
connection).
connection).
service).
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