QTR Purge Vs Flush

I’m switching my 3380 from K7 inks to Pro inks and want to clear out the K7 ink. I also have a 3800 that is currently color that will be switch to the K7 ink set for matte only. I see references to both Purge and Flush files and I have downloaded both. The question is how is Purge files different from Flush and in which scenarios would each be used.


With the 3880 just run 3-5 power cleanings to flush the lines