Replacement of perfect prep filter

[Emily11b]

I have been using the prefect prep day and night machine for a couple of weeks now and needed to replace the filter. I have followed all the instructions on the machine, clicked the new filter into place (made sure I heard it click) filled the tank with cold water but the water is not flowing through? So I I can't go to priming the filter as the machine is not recognising the water in the tank? Any suggestions on what I should do?

The two things that spring to mind (I haven't used one for about a year and a half now) but did you remove the sticker off the filter? And also I remember having to submerge the filters in a tall glass or jug of water prior to installing to allow air bubbles to escape - maybe you've got an airlock? X