GESTRA NRR 2-40 - Troubleshooting Operational Faults; Fault Finding List and Remedies

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Fault: Incorrect function at analogue output. The connected actual value indicator shows
incorrect readings.
Remedy: Correct the switchpoint settings.
Correct the control range setting of the electrode.
Fault: Switchpoints and the indicated actual value drift steadily towards 100 %
Remedy: Dirt has deposited on the electrode rod. Remove the level electrode and clean the
electrode rod.
Fault: MAX level is signalled although the water level is below the MAX limit.
Remedy: Dirt has deposited on the electrode rod. Clean the electrode rod.
Sealing / insulation of level electrode defective. Replace level electrode.
Fault: Liquid level below MIN switchpoint but no switching function.
Remedy: Check the installation of the level electrode. Maybe there is no vent hole in the protection
tube. If electrode is installed in external level pot: Open the isolating valves.
Fault: Level exceeds MAX switchpoint but there is no indication.
Remedy: Level switch defective. Replace equipment.
If faults occur that are not listed above or cannot be corrected, please contact our service centre
or authorized agency in your country.
Equipment does not work accurately
Operational malfunctions
The equipment is working as twoposition (onoff) controller
Fault: The feedback potentiometer is defective or not connected.
Remedy: Wire equipment according to the wiring diagram. Check feedback potentiometer.
Fault: In spite of correct wiring and commissioning of the equipment an error message is indicated.
Remedy: The error message is caused by the highfrequency interference coming from the system.
For the interference suppression of the voltage supply we supply hingedshell ferrite rings,
stock code # 147253.
The 230 V supply lines should be looped five to ten times through the ferrite ring. If sev
eral controllers are used in one system, they can be fed from the interference suppressed
supply lines.
For the interference suppression of the bus line we supply hingedshell ferrite rings, stock
code # 147254. The hingedshell ferrite rings are clamped onto the bus lines near the
terminal strip of the control unit.
Equipment is not working – a malfunction is indicated
Equipment does not work – no function
Fault: LED “Power ON” is not illuminated.
Remedy: Switch on mains voltage. Wire equipment according to the wiring diagram.
Fault finding list for troubleshooting