First off, the back heat on the 41 quart tubs is not going to be enough unless you are in an extremely warm room. You will most likely need to convert it over to belly heat. I use 1 foot of 12" flexwatt on my 41 quart tubs.
Error code 2 means the sensor has shorted. You can find the info here: http://www.spyderrobotics.com/produc...tnd_manual.pdf