I perhaps should have ventured here first. I have a 2 print head clog 7890. I ordered and used the piezo flush cartridges with no results. I have asked for a followup response but have received no answers for a week or so. I’m at the point of considering a remap and using this printer if possible for piezography. I hate to trash such a marvelous piece of equipment if it is not necessary. Here is the url of my requests so far.