The recommended procedure when switching from color to Piezography inks is to install a set of carts filled with PiezoFlush, and do an initial fill to purge ink to flush the internal ink system. Print a nozzle check to confirm all channels are fully printing pink PiezoFlush, and colors have been purged, then install the set of Piezography cartridges and do another initial fill cycle to purge flush fluid and get Piezography ink from carts to the print head.
The flush carts can be stored and reused later if you ever need to flush or safely store your printer if it won't be used for a while.
Please let me know if you have further questions or there's anything else we can help you with.
Best regards~ Dana