Knowledgebase
How to change the number of comments per page in Drupal
You can change the number of comments per page by editing the settings for the content type(s). The preconfigured article content type that comes with Drupal, for example, displays fifty comments per page by default. To change that number to a higher or lower one, log in to the admin panel of your Drupal, click on the Structure tab in the top navigation bar and on the page that opens click on Content types. On the next page click on the edit button for the particular content type (e.g. article). This will display the global settings for the content type. Scroll to the bottom of the page and click on the Comment settings button that's on the left. This will show the comment settings. Use the Comments per page drop-down menu to select the desired number and click on the Save content type button to save the change.
This will update all the existing items (nodes) from that content type changing the number of comments per page for all of them. The new setting will also apply to all nodes of that content type that you publish in the future.