Piezoflush effectiveness after expiry date?

I currently have a set of flush carts in my 7880 as I’m trying to clear a stubborn blocked nozzle in the LM channel, and to flush out the ink lines and (only 3-month old) dampers. However, after doing the changeover from ink to PF, and running a couple of power cleans, I now have 99% non-printing in six of eight channels - only VM and Y are printing a nozzle check. I’ve also left a PF pad under the head for a number of days (keeping it dampened), done the ‘shoeshine’ clean a couple of times, but with no improvement.

I have some fresh PF en route to me, but I’m wondering, for future reference: Does the effectiveness of PF as a solvent for dried ink noticeably reduce after its expiry date? The PF I’m using has an expiry date of 04/2016.



PiezoFlush chemistry is very stable as long as it is kept sealed. So yours should still be effective.