DC / AC pump combo in same well



I am thinking of running two pumps down the same well. I was going to drop the DC solar pump down to about 200' and the 3/4 HP standard well pump down to around 175' and pump into a large tank. Does anyone see any problems in doing this. Is there any pump controller that will handle two float switches? For instance when top float switch is on the small DC pump would run, and fill tank until upper switch is off. If we were using too much water when the lower switch is on then the big AC pump would kick on. The AC pump would run until the upper float switch was off. Thank you in advance.

Comments

  • System2System2 Posts: 6,290 admin
    Re: DC / AC pump combo in same well

    Is there room in the well for the upper pump with the wire and pipe from the lower pump already in the well? And, if so, you would have to do the installation with the knowledge that the 3/4 hp pump, will always want to give a sharp rotary jerk in one direction when it starts and another in the opposite direction when it stops (equal and opposite reaction to the rotating parts in the motor and pump) and that unless the installation is very well done, this motion will chafe through the wire and or pipe from the lower pump. There are expanding, rubber devices, called Torque Arestors, to restrict and reduce this motion, by jambing between the well casing and the pipe just above the pump, but again, what about the pipe and cable already in the well. I am assuming you have a standard 6 inch diameter drilled well.
    Just a "heads up" to consider.
    Your "float" idea should work OK, like you said, have the lower one control the big pump and the upper one the DC pump..
    Good luck
    Wayne
  • System2System2 Posts: 6,290 admin
    Re: DC / AC pump combo in same well

    I see how your two float switches will start your pumps (assuming you solve the problem of installing your upper pump with the lower pump pipe and cable in the way) but how will you shut them off without high level shutdown switches?
  • System2System2 Posts: 6,290 admin
    Re: DC / AC pump combo in same well

    Correct Cana it is a 6 inch well diameter. I will look into the Torque Arestors. I still do not know how to wire up the two switches and pumps. I know how to wire up the DC solar pump and the top switch. I do not know how to have AC pump start when lower switch is tripped and stop when upper switch is tripped.
  • System2System2 Posts: 6,290 admin
    Re: DC / AC pump combo in same well


    TCurran, I am not sure how to controll the AC pump on and off yet.
  • System2System2 Posts: 6,290 admin
    Re: DC / AC pump combo in same well

    One way to control your AC pump;

    There are differential float switches that would do the job for you but they are hard to install in a plastic water tank (if that's what you are using) without creating a place for critters to get into your tank. They are also expensive.

    But a relay with at least one normally open contact will do the job.

    Wire your Hi level and Low level switches so both switches close when the level drops and put them in series with the AC motor starter.

    Wire the relay coil in parallel with the motor starter and place it's normally open contact in parallel with the lower float switch.

    When the level drops and the lower float switch closes (the upper has been closed since the water level started to drop) the pump motor and relay are energized.

    As soon as the level starts to rise the lower float switch will open but the relay contact across it will continue to hold in the motor starter until the level rises to open the Hi Level switch.

    That will shut down the AC pump.

    A sketch would make it clearer but I don't know how to insert links in this forum.
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