Circle and arc patterns in outer shells

[Horia]

Hello, I have a WASP Delta 2040 printer and in all my prints there are circles and arcs patterns emerging.
Here are some photos:

received_1063126637065552.jpg
Link: https://drive.google.com/file/d/0B_j...ew?usp=sharing

received_1063126667065549.jpg
Link: https://drive.google.com/file/d/0B_j...ew?usp=sharing

In the photos above you can see the arcs.

received_1063127287065487.jpg
Link: https://drive.google.com/file/d/0B_j...ew?usp=sharing

In the photo above you can see the circle on the left side.

I saw that there are other users of this 3d printer that have the same problem but couldn’t find any information about this. If there is a troubleshooting guide about this please share it.
My printer is currently in service so I can't test anything but any info would be appreciated.

Thank you for reading.