The Power Cleaning feature may improve print quality in the following cases.
When most nozzles are clogged.
When you have performed a nozzle check and head cleaning 3 times and waited for at least 12 hours without printing, but print quality still did not improve.
Before running this feature, use the nozzle check feature to check if the nozzles are clogged, read the following instructions, and then run Power Cleaning.
The Power Cleaning uses more ink than the print head cleaning.
Select Maintenance on the printer's control panel.
To select an item, use the 
buttons, and then press the OK button.
Select Power Cleaning.
Follow the on-screen instructions to run the Power Cleaning feature.
After running this feature, run the nozzle check to make sure the nozzles are not clogged.
For details on how to run the nozzle check, see the related information link below.
If print quality has not improved after running Power Cleaning, wait for at least 12 hours without printing, and then print the nozzle check pattern again. Run Print Head Cleaning or Power Cleaning again depending on the printed pattern. If quality still does not improve, contact Epson support.
You can also run power cleaning from the printer driver.
Windows
Maintenance tab > Print Head Cleaning > Power Cleaning
Mac OS
Apple menu > System Preferences > Printers & Scanners (or Print & Scan, Print & Fax) > Epson(XXXX) > Options & Supplies > Utility > Open Printer Utility > Print Head Cleaning > Power Cleaning