I just got back from a vacation of eleven days. While we were gone, I turned off my skimmers and set the pump to run about four hours each night. On our return, the breaker to the pump had been tripped and our friend who was watching the house said there were no electrical problems until today (when my pump breaker goes, so does the air conditioner on that side of the house, though that's another issue). When I reset the breaker and switched the pump on, there was a brief flash and puff of smoke from the back end of the pump where the electric cables come in, and the breaker threw again. Not wanting to cause further damage, I switched the pump off and left it as is. I'm mystified: there is still water in the pump, so I don't think it ran dry at any point; I regularly run the pump much more than four hours per day without trouble. If you have thoughts as to the cause (a timer "off" switch that magically stopped working during vacation?), or as to what my next steps should be (do I need to replace the pump, get the motor rebuilt, call an electrician?), I would greatly appreciate it.