Grundfos DDA 7.5-16

English (GB)
42
8.1 List of faults
8.1.1 Faults with error message
Display in the
"Alarm" menu
Possible cause Possible remedy
Empty
(Alarm)
• Dosing medium tank empty • Fill tank.
• Check contact setting (NO/NC).
Low level
(Warning)
• Dosing medium tank almost empty
Overpressure
(Alarm)
• Discharge valve blocked
• Isolating valve in discharge line
closed
• Pressure peaks due to high
viscosity
• Max. pressure set too low (see
section 6.8 Pressure monitoring)
• Replace valve if necessary (see section
7.4 Perform service).
• Check flow direction of valves (arrow) and
correct if necessary.
• Open the isolating valve (on the discharge
side).
• Enlarge diameter of discharge line.
• Change pressure setting (see section
6.8 Pressure monitoring).
Low
backpressure
(Warning/alarm*)
• Faulty diaphragm
• Broken discharge line
• Pressure differential between
suction and discharge side too low
• Leakage in the pressure loading
valve at Q < 1 l/h
• Deaeration valve open
• Change the diaphragm (see section
7.4 Perform service).
• Check discharge line and repair if
necessary.
• Install additional spring-loaded valve
(approx. 3 bar) on the discharge side.
• Close the deaeration valve.
Air bubble
(Warning)
• Broken/leaky suction line
• Strongly degassing medium
• Tank dosing medium empty
• Check suction line and repair if necessary.
• Provide positive inlet pressure (place
dosing medium tank above the pump).
• Enable "SlowMode" (see section
6.6 SlowMode).
• Fill tank.
Cavitation
(Warning)
• Blocked/constricted/squeezed
suction line
• Blocked/constricted suction valve
• Suction lift too high
• Viscosity too high
• Enable "SlowMode" (see section
6.6 SlowMode).
• Reduce suction lift.
• Increase suction hose diameter.
• Check suction line and open isolating
valve if necessary.
Suct. valve leak
(Warning)
• Leaky/dirty suction valve
• Deaeration valve open
• Check valve and tighten it up.
• Flush system.
• Replace valve if necessary (see section
7.4 Perform service).
• Check O-ring position.
• Install filter in suction line.
• Close the deaeration valve.
Disch. valve leak
(Warning)
• Leaky/dirty discharge valve
• Leakage in the pressure loading
valve
• Deaeration valve open
• Check valve and tighten it up.
• Flush system.
• Replace valve if necessary (see section
7.4 Perform service).
• Check O-ring position.
• Install screen in suction line.
• Close the deaeration valve.
• Install spring-loaded valve on the
discharge side.
Flow deviation
(Warning)
• Considerable deviation between
target and actual flow
• Pump not or incorrectly calibrated
• Check installation.
• Calibrate the pump (see section
5.3 Calibrating the pump).