I've had this happen. Most likely the coil overheated. You might want to check to see if your switch controller button has stuck, causing the coil to stay activated continously...which they are not designed to do. This is what happened to me. As to the fix....if this is the case, the coil has somewhat collapsed from the heat, and replacement of the coil assembly is the solution. I think the coil assembly cost about $12.00 and is not a difficult job to do. (Replace the switch controller though if the button sticks, before changing the coil so it doesn't happen again). Hope this helps.