Here are all the steps to get a working OC filter:

1) You need to make sure, you have correctly created a filter:

- Create filters
- Assign filters to products
- Assign filters to categories

2) If you are running a multi-store, you need to make sure that filter categories are valid for each store.

3) Then you need to export module to Page Builder:

http://docs.themeburn.com/burnengine/content-blocks/opencart/

BR,
ThemeBurn team