If you go to the EFM website they have online manuals. http://www.efmheating.com/manuals.html On page 17 of the 520 manual it shows the wiring diagram for an L6006. The manual is a pdf document. Sometimes it takes forever to open.
Yes that will shut down the stoker if the water temperature goes below a certain temperature, sensing an outfire. It's very easy to wire up if you look at the schematics in the manual.