Quote Originally Posted by suzuki4life View Post
heat tape wasn't on a dimmer switch. It was absorbing max voltage.

max voltage+ reduced airflow in a rack setup+ age of heat tape= malfunction.

To properly setup heat tape (according to Bean Farm), you must regulate the temp to below 95 degrees. Then use the thermostat as a fail safe for overall temp of the tub.

Surges do not have to be huge to cause damage. Small spikes rarely trip surge protectors. This is the reason many computer guys have dumped the common surge protectors and changed to power conditioners.
I have read the same and Have seen from 95 to 100 for a max temp on the tape. This is my thought too that with the on off t-stat and perhaps older less efficient tape during one of the cycles it failed.

I run fail safes for ever t-stat and monitor not just the tub temps but the tape its self and I do not like seeing over 100 for any more than 10 min or so. I also when I clean the rack lift the tape (clean under it) and check it very carefully. Racks save space but in my experience they take far more effort.