General Faults - Grundfos DDA 7.5-16 Installation And Operating Instructions Manual

Display in the
"Alarm" menu
Pressure sensor
(Warning)
Motor blocked
(Alarm)
Bus error
(Alarm)
E-Box
(Alarm)
Cable break
(Alarm)
Service now
(Warning)
* Depending on setting

8.1.2 General faults

Fault
Dosing flow too high
No dosing flow or
dosing flow too low
Possible cause
• Broken "FlowControl" cable (see
fig. 11)
• Sensor defect
• Pressure sensor not correctly
calibrated.
• Backpressure greater than
nominal pressure
• Damage to gears
• Fieldbus communication error
• E-Box connection error
• Faulty E-Box
• Defect in analog cable 4-20 mA
(input current < 2 mA)
• Time interval for service expired
Possible cause
Inlet pressure greater than
backpressure
Incorrect calibration
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
Faulty calibration
Deaeration valve open
Possible remedy
• Check plug connection.
• Change sensor if necessary.
• Calibrate pressure sensor correctly (see
section 6.8.2 Calibration of pressure
sensor).
• Reduce backpressure.
• Arrange for repair of gears, if necessary.
• Check cables for correct specification and
damage; replace if necessary.
• Check cable routing and shielding; correct
if necessary.
• Check plug connection.
• Replace E-Box if necessary.
• Check cable/plug connections and
replace, if necessary.
• Check signal transmitter.
• Perform service (see section 7.4 Perform
service).
Possible remedy
Install additional spring-loaded valve (approx.
3 bar) on the discharge side.
Increase pressure differential.
Calibrate the pump (see section 5.3 Calibrating
the pump).
Deaerate the pump.
Change the diaphragm (see section 7.4 Perform
service).
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.
Enable "SlowMode" (see section 6.6 SlowMode).
Enable "SlowMode" (see section 6.6 SlowMode).
Use hose with larger diameter.
Install spring-loaded valve on the discharge side.
Calibrate the pump (see section 5.3 Calibrating
the pump).
Close the deaeration valve.
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