I just installed a ET-2803, so here are the steps I used.
First turn off MAC Address Filtering on the router
Next, turn on SSID broadcast for the 2.4 GHz band.
Put ink into the printer, and paper.
Download the Epson software from the Epson Web Site.
It should find the printer, charge the ink, and let you set up the SSID and password.
Now print a Network Status page, using the keypad on the front of the printer.
This should have the printers MAC Address at the bottom.
Add this MAC address to MAC Address Filtering, and turn on.
Turn off SSID broadcast
Now go to DHCP reservation, and put in a Reserved DHCP address for the printer, using its MAC Address.
This will give the printer the SAME DHCP address every time it requests one.
Restart printer and computer
Now go to "Applications", "Epson Software". then to "Epson Scan 2" , NOT "Epson Scan"
I also suggest turning on "Quiet Mode" on the printer front keypad, this may allow it to last longer, less wear on the printhead