If you don't have a pump but want to run a water cooled system you can always set up a siphon between two buckets that will give you way better cooling than nothing at all.
I avoid running any water cooled system for longer than is required to just confirm that it works as to do more is to ask for trouble not covered by warranty.
Hopefully you can't be traced by your supplier from this post as if you can your warranty is void ;-)
Regards,
Nick