I have a 240 volt submersible water well pump. I hook it up directly to 240 to see if it'll run. It should run until I turn off the power, but it doesn't. It runs for around three seconds and then it turns off for 10, runs for 3 seconds turns off for 10 and so on. What's the problem? I have a 20 amp breaker.

  • Can you post a photo of its nameplate? Also, is it overheating when it's cycling like this? – ThreePhaseEel May 27 '17 at 21:59
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    If you're running it un-submersesed it's probably over heating, or if it has been run dry for any length of time the motor could be shot. Something could be caught in the impeller, or the bearings could be worn out. – Mazura May 27 '17 at 22:12
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    Posting from your phone doesn't excuse a total lack of punctuation. Please show more respect for your readers in the future. – isherwood May 28 '17 at 2:54
  • If it is still in the well, you need to remove it, take it to a pump shop or a motor repair shop. You may need a new pump, capacitor, or some other part. – d.george May 28 '17 at 11:43

You need to have a submersible pump submersed when testing. Most deep well pumps ALSO need adequate back pressure to limit the current they draw (normally provided by that long pipe up the well to the surface.)

Running dry is bad for all submersible pumps, and "in a bucket" (i.e. with no output restriction when outside of the well, or without adequate head in a well) is bad for most. They expect to be in water (generally near 10C/50F) when operating, and that water serves as lubricant and coolant.

Your on/off cycling is probably caused by the pump's protective circuitry shutting it down due to overheating.

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