Auto cache on all pages

Hi,

I have question about how to setup a Litespeed cache to don’t purge cache automatically after 1-2 hours. If I open all my pages on a site and cache are generated, it goes so fast (around 1s). After 1-2 hours site is slow like cache doesn’t work or was purged automatically (I didn’t edit anything or update). In my options I setup it for 1 week, not hour. Could you explain me how it works?