Shark Vacuum Cleaner (NV680UKT 40) leaving black marks

[Another Dave]

Hi All,

Make: Shark
Model: NV680UKT 40
Issue: Vacuum cleaner keeps leaving black lines when moving it while it's on. I can't seem to figure out what's causing this to happen.

See sample YouTube video

Regards

Dave

 

[Another Dave]

##UPDATE##

This issue has been resolved after identifying a blockage reducing the suction.