Question about Medisana BU 512

See operating instructions (link below) under section "Troubleshooting". If the fault cannot be rectified, the appliance may be defective and must be returned.

https://www.medisana.de/out...

This question must be asked of the manufacturer and not the user.

The hose must be inserted into the socket on the left (not at the back). If necessary, insert new batteries. If this does not work, contact customer service

Device is very good. Thank you