Heater pads will not " cook" the brew.Otherwise a heater belt would, but from the middle.Neither put out anywhere near enough power to do so,if you have either that does get rid of it now.!Mr Wibble said:My heater pad sits on the compressor hump (in a chest freezer).
It seems to do the job ok, but my temperature probe is inside the fermenter.
I think I read here, or someone told me, that having a heater pad under the beer can "cook" it (not literally), it's gets way too warm.
Obviously a belt is not a pad, so maybe test it with a fermenter full of water or suchlike.
Heater pads and belts don't put out that much heat,they heat at a low output and therefore take a long time to heat the contents of the fermentor ( liquid mass) .
If the fermentor is insulated this will help in both heat loss and cold gain,heat pads and belts work in the simple principle of heat rises,when they are trying to do this they have to first heat the entire fermentor contents ( mass) the yeast activity adds some minimal temp increase,as the wort slowly warms up convection causes the wort to mix into itself , again heat rises and cold sinks so the heater pad/ belt simply speed up/ help the fermentation process .