My pool is at a vacation home in NY State, so it is mainly used weekends. The pump is controlled by a timer, and operates from 7AM to 5PM.
On Friday a few weeks ago, I found the circuit breaker had popped. I was able to reset it, so the pump was back in operation, and ran perfectly at least through Sunday.
The following week, I again found the circuit break popped. Again I was able to reset it, and the pump was back in operation. However, on Saturday morning, the pump once again popped the breaker, and this time I couldn't reset it. The timer showed that it was at start-up.
I disconnected the pump at the switch box next to the pool, and was able to reset the breaker. I tested the voltage at the switch box, and it was 115-120v. (My pump motor is set correctly). This also indicated the problem was in the pump itself.
I attached a plug to the end of the pump wires, and the pump started right up when I plugged it in the next morning.
It's a relatively new pump. My first Super Pump lasted 17 years. Its replacement was put out of action after 8 years because a garter snake crawled inside, and got barbecued.
I've checked the start capacitor, and it's okay, within tolerances.
I've installed a backup pump to get the pool running again, and haven't had any problems with the backup since.
Can anyone give me a suggestion what to check next? The pump runs perfectly, when it runs. What condition might be present at start-up that would cause it to pop the breaker?