I need to know what chemical will help dissolve calcium deposits from urinal pipes that are in the wall. Here's the story. I work at in a large industrial setting as a janitor and we have the "less famous" waterless urinals and we're finding when we change the "filters" that there is calcium build up causing the urinal to overflow. The pipes in the wall are pvc and there is no clean out pipes.
Any help will be greatly appreciated.

Thanks
Mi_smiley