Timer trips breaker

Jan 3, 2013
126
Any ideas to get me started diagnosing are welcome. Every time my intermatic timer reaches the "on" tripper, the pump circuit breaker trips. However, if I manually switch the pump to on, it runs fine with no circuit breaker issues. What the heck could be causing that?
 
It's unlikely that the timer is getting wet consistently. If, by some freak accident, it had gotten wet at some point, it would be dry by now.
I guess I did not even realize the timer itself is on the same circuit as the pump. But I guess that makes sense.
I don't think the circuit is overloaded because nothing has been added. Almost sounds like a short because it is so instant.
Do timers go "bad"? I'm confused.
 
Further diagnosis, the pump often does not turn over when "cold" starting. Causes the breaker to trip. If i turn the shaft a bit manually, it will start on the next try. A barely noticable little bit of resistence fromt the shaft but in general it turns freely. I am going to replace the capacitor first and see if it works, otherwise a new motor is probably in my near future. Which I am not looking forward to. There will be a lot of busted knuckles and tears.
 
Further diagnosis, the pump often does not turn over when "cold" starting. Causes the breaker to trip. If i turn the shaft a bit manually, it will start on the next try. A barely noticable little bit of resistence fromt the shaft but in general it turns freely. I am going to replace the capacitor first and see if it works, otherwise a new motor is probably in my near future. Which I am not looking forward to. There will be a lot of busted knuckles and tears.

Could just need bearing and seal replacement. Much cheaper than a motor.
 
In case it helps the next guy: the problem turned out to be with the seal plate. At some point in the past, the pump has been apart and somehow one of the bolt holes in the seal plate was damaged. It looks like they used some JB Weld to prop up the thread but this failed over time and allowed the seal plate and motor to become misaligned. The misalignment caused the impeller to begin rubbing which felt and sounded like a worn shaft or motor seal. Eventually the rubbing was too much for the motor to overcome.
 
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