Posted by Mike Keller on 02/26/2010 at 13:12:55:

David:

There should be one or two thermal cutouts (TCOs) in the heater. In order for thermal runaway to occur, the TCO would need to have failed. The manufacturer's data will provide the location(s). Once they are found, a simple x-ray can valdiate that.

What is the probabability of the pump leaking in the vicinity of a utility attachment cord or power tap? Did the circuit breaker that handled the branch circuit for this trip?

I've dealt with one the wound up having series arcing in the plug where it was attached to a power strip.

Hope this helped.