Since nobody had a better idea, I called the dealer to come take a look, and the tech said it was certainly the heater because when he touched it, it nearly burned his fingers and he says the heater should never get that hot... So nearly $600 and 2 days later it trips again and needless to say I'm not a happy camper! Now he's "pretty sure" it's a control head which will be pretty much the same price as the new heater!! I'm not exactly jumping with joy at something like $1,200 in repairs less than a year after the warranty expired...
I still have the heater he took out last week and I'm thinking I'm going to tell him to put that back in and return the new one to his inventory for credit against the control head he's guessing is the problem this time. It sounds reasonable to me -- I mean at $600 a week in repairs I might as well go looking for a whole new tub! Am I barking at the moon, or do you think a reputable dealer should be willing to take back an expensive - less than week old - part that they installed needlessly?