I used a Konwin FH03 fan space heater for a short period of time, and when finished, I turned it off by turning the on/off knob to the left. I then exited the room, but returned a short time later and noticed the heater element was still glowing, and there was a smell of smoke and burning plastic. I pulled the cord from the wall socket and tried to lift the space heater from the surface it was on, but it was too hot to the touch. It was evident that when I turned the on/off switch “off” the fan turned off but the heater coil did not. The plastic frame had melted partially and dripped onto a nearby surface. If I had not unplugged the device when I did, I’m sure that the frame would have melted enough to cause it to be unstable and fall onto the carpet, and/or the melting plastic itself would have resulted in further burning, and a potential serious fire.