Just found some interesting info on the A419 you all should be aware of. There is a sensor failure mode that will either leave the output on or off in the event of a sensor failure. According to the litature the default setting will turn it full on in the event of a sensor failure (FRIED SNAKE) These units were comonly used in comercial freezer units and walk in freezers. Heres a link for the controll in pdf. Check page 4 and 8 under SF for sensor failure . I believe you have to set it to ZERO for de energized. So if you have a heated room with the controller on heat tape and have this set properly , When the sensor fails after 1 minute it will shut it down completely. Something to think about. Worst case senario would be if you were using this controll to controll a space heater and had a sensor failure in the default mode it would leave the heater on continuously.Heres the link. Did not post this as a negative remark against the controller ,I just thought if you were unaware it could cost you big time!!! http://cgproducts.johnsoncontrols.com/MET_PDF/1201614.PDF Its 12 pages in PDF