My pool pump runs for 20 seconds then shuts off, what is wrong?

Question

My pump was working fine and then it just stopped working. It will run for 20 sec. then shot off. I replaced the wiring because it was bad, and still same problem. Replaced the pump and still the same problem. (inground)

Answer 1

There are at least 3 maybe 4 posibilities. You replaced the bad wiring... What guage wire did you use? All wire will resists the flow of electricity. The smaller the wire the more resistance. This is the reason you might touch an extension cord and it is warm. Or even hot. If you used 12 guage or smaller wire (sizes run in reverse, 14 is smaller than 12, 16 is smaller than 14 and so on) you may have restricted the line and your pump is not receiving enough power to operate.

If the wires that lead to the pump are excessively long, this can also cause power drop. You can use a tester to check voltage and Amps  at the start of the line and again at the pump. Is there much drop? Shorten the wire if posible.

Your breaker may not be adequate. Check the pump housing for a lable that shows how many Amps it requires. Your breaker will need to be at least the same. If the pump requires 22 Amps, you will need a 25 amp breaker for example.

The intake water line is obstructed or too small in diameter. Water flow leaving the pump can be restricted to a point. The input line should not be.

I wish you had mentioned where the shutoff is occuring. Does the Breaker flip off? Is the internal reset button thrown? Is there a switch or timing device that activates the pump remotely that is failing? If you would add this information, I can go into much better detail.

Answer 2

You say that you replaced the pump, but did you replace the motor as well?  It sounds like an internal overload is tripping, and that is a temperature-based overload.  The motor should not get so hot in 20 seconds to trip this, so there may be a bad winding in the motor.  It is possible that the overload is weak possibly from having been reset too many times before?

Answer 3

sounds like you have 2 bad motors that are overheating some motors have thermal cut off switches....unless you have an extremely long run of wire to pump like way over 100 feet.