[CentOS] OT: default password for HP printer

http://lmgtfy.com/?q=officejet+8620+manual

I concur - I don't believe there is a password on the EWS.
You should be able to print out the network settings from the LCD control
panel, which will be 2 or 3 pages and includes info you need like MAC
address[es], default and user-set passwords, IP address[es], et cetera.