You DO NOT "manually clean the heads", if by that you mean somehow intervening externally. First, if you got the manual with the printer, read everything they say about cleaning the printhead using the controls in the printer. If you did not get the manual, download from the Epson website and do the same.
Not knowing anything about the prior condition of this printer, how it was transported, when it was last used, how well it was maintained, it is impossible to provide any kind of diagnosis. As a matter of standard procedure, however, now that you have cleaned the heads once, cancel any cleaning prompts; run a print - forget about what it looks like - doesn't matter. Turn-off automatic cleaning from the panel controls following the instructions in the manual. Print a nozzle check using either the Epson 4900 utility on your computer or from the menu on the printer's control panel (see the manual for instructions). If the nozzle check shows broken lines, either print the affected pairs, or do a general cleaning. Run another nozzle check and see whether there are broken lines. If not, you are fine. If there are, run another print and then run another cleaning cycle. Repeat this pattern three times. If you still don't have a cleared print head, do a power clean after running a print. It uses a lot of ink, but your last resort before calling in a technician. After the power clean, run a nozzle check. If this still shows broken lines, call Epson Pro Graphics for help.