al - i had this happen - i setup a new tank in the basement and plugged everything in - the heater came on - i thought all was good - i went to bed, woke up and checked the tank...it was freezing...only my problem was i plugged everyting into a switched outlet - when i went to bed i turned out the lights (and the tank)...it was like a scene from christmas vacation - my wife figured it out...not exactly the same - but funny...