Most helpful critical review
80 of 80 people found the following review helpful
Actually only 1 heat level; burned out with bad smell
on October 31, 2007
First, I should note that it is likely that various configurations of this product are being sent out under the same product name, probably based on whatever is convenient for the manufacturer due to availability and cost of parts and material. Therefore, other customers may have received a different pad, and therefore had different experiences, than I did. As a side note, the product I received had no auto shut off; as apparent from the reviews, some do and some don't.
A rather striking feature discrepancy is that my pad only had one heat level (just on or off), despite having a three level switch controller and a product description to match. I dissected the pad due to the fact that it had burned out (more on that later), and found that although the controller had the circuitry necessary for three levels, the pad itself did not. Two of the three wires going to the pad were simply connected together within the pad, and there was only one heating element. Given the design of the controller, for three heat levels, there would have to be two heating elements. This finding was consistent with an observation I had made months earlier when I plugged the product into a watt meter: no matter the setting, the heating pad drew the same power. I'm certain of these findings; I am an electrical engineer and this is a very simple electrical device.
Now to describe the device failure. The pad was on the floor, about half covered with a hand towel, room temperature 65 degrees F. Upon noticing an unpleasant odor, I removed the felt cover and found the pad was getting extremely hot in one area and the white vinyl case had turned brown at that location. I then cut open the controller and the pad and determined its operation and failure point. The pad has two thermal protectors, also called thermal cutouts or thermostats. One of these was the point of extreme heat; the insulation had charred around it, as would be expected. It is likely that this thermal protector, a Pepi E-series, was either the wrong part or mis-calibrated.
I am left with a concern that this manufacturer may be changing product components and even features without proper regard for consumer rights and device safety.