Lava rock should be placed only ONE LAYER deep, just enough to cover the burner tubes.
DO NOT place lava rock on top of the pilot cage.
WARNING Lava rock is porous and holds moisture. If you light the burner with wet lava rock, the moisture inside turns to steam quickly and can cause the rock to pop and crack. It’s best to keep the lava rock dry when not in use. (another reason to buy one of our weather covers)
WARNING Our burner has been tested and CE approved for use with lava rock. DO NOT replace the lava rock with anything else as this could render the burner inoperative or dangerous.