Originally Posted by BadNick

I noticed on the lamp in my boys' room, that once the original bulb got a little loose and it stopped melting the paraffin "lava". I screwed it in snugly and it's worked now for another year or so, still working. I bet the bulb has to have high enough wattage or it will not melt the lava. When I had it out, it was a smaller than normal but hot running bulb, not sure what size. Also make sure the bottom of the bottle is down as far as designed so it gets hot enough. If that doesn't work, buy a new one.