Technical FAQs

Ask a Question

What is the cause for a flashing U on the display of a Berger Lahr Twinline drive?

The Berger Lahr Twinline Drives monitor the external 24 volt power source which is used to power the drive's processor.
If the 24 volts is interrupted or below an acceptable level of 18.2vdc then the drive will respond with a fault code on the LED display and show a flashing U.
When the display flashes "U", this is an indication of an issue related to the external 24 volt power supply.

If the 24 volt power supply has too much ac ripple, as a result of faulty filtering capacitors, this can also result in the drive reporting fault code U
Please check the 24 volts to make sure it is stable and within acceptable range of 20 v to 30 v dc 

Rev 6-4-18
Was this helpful?
What can we do to improve the information ?