Burkert 8718 Manuel D'utilisation page 44

problem
No flow-rate available
Actual value fluctuates
Set-point value = 0%,
flow-rate still available
Set-point value = 0%,
valve is closed,
no flow-rate available;
however, actual value
output indicates a low
flow-rate
Set-point value is not
reached
Table 10: Malfunctions
44
possible cause
The set-point value is below the limit for
the zero point shut-off.
The device is in an operating state other
than standard controlled operation.
The pipelines have been sized too large
or may not yet have been completely
deaerated.
FE connection not correct.
The controller is continuously correcting
malfunctions in an unstable pressure
supply, e.g. by pumping.
The residual ripple of the power supply
voltage is too high.
The operating pressure is above the
maximum operating pressure of the valve.
The mounting position of the device is
incorrect.
A fluid is used other than that designated
by the calibration.
The filter is blocked.
The primary pressure is too low.
The back pressure is too high.
english
Type 8718, 8719 / 8708, 8709
Maintenance, Troubleshooting
remedial action
Increase set-point value to > 10% of the
nominal flow-rate.
Check operating state, see also Chapter
8.3. Functions of the LFC / LFM.
Deaerate lines.
Change pipe size.
Connect FE to the earthing point (as
short as possible, wire at least 2.5 mm²).
Connect suitable pressure controller
upstream.
Install buffer tank to absorb pressure
fluctuations.
Use power supply with a smooth output
voltage at the required power.
Reduce the operating pressure.
Return device to the manufacturer to
have the fault repaired.
Install LFC in the calibrated mounting
position and run an Autotune function to
adjust to the operating conditions.
Return device to the manufacturer for
recalibration for the operating fluid.
Clean or replace filter.
Increase primary pressure to calibration
pressure.
Check system components for soiling on
output side and if required clean.