A burner tube and door assembly for a water heater includes a burner tube and a fuel supply line in telescoping relationship to define a tube junction. The tube junction extends through the door of a water heater. One of the tube and line includes an enlarged portion. A lock ring applies a radially-directed force around a portion of the tube junction. The enlarged portion and lock ring are on opposite sides of the door to secure the door to the burner tube and fuel supply line. The enlarged portion and lock ring apply a compressive load to the door to resist rotation of the door with respect to the tube junction.