Can't you just fill the tanks, or drop the inlet lines in a jug of IPA and do the manual flush? Pretty simple procedure.
Here's their link to their YouTube instructional page.
https://www.youtube.com/channel/UCRHrjK4_678yDzN4TkYnVvA
I first flush the lines up to the secondary filters using the purge button. Then flush the heads with a syringe. You can then reconnect the lines and purge a bit more to make sure everything is filled with the solution.
When switching back to ink I always replace the filters after b/c it can be a task to get all the flushing fluid out and 100% ink back in the lines.