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Thread: Well Pumps: 120 VAC vs. 240 VAC

  1. #1
    DIY Member BillyJoeJimBob's Avatar
    Join Date
    Jul 2011
    San Antonio, Texas

    Default Well Pumps: 120 VAC vs. 240 VAC

    We've inherited a property and are in process of getting the shallow well working. It's been vacant/abandoned for about 8 years. I have 3 pumps.

    The first one is an old, broken Gould we found under the house. The metal of the pump housing is physically cracked; it looks like it might have frozen with water in it. I've verified the motor will run at 110 VAC. I mention this because it may be possible to change-out the pump part (it's bolted to the motor), and re-use the motor at some point.

    The second is the old pump's replacement, a Grundfos Jet pump. It's logic circuits seem to be screwed-up, but that may be because I've only applied 110 VAC. The motor also runs for this one.

    Finally, I bought a new 1 HP pump from Lowes. It was rated at 110 VAC.

    From what I have read, it seems that the idea that pumps are either 110 or 220 is fairly "soft"; that they can be wired either way. Is this true? If not, is there any way to tell if a pump is one or the other? Originally I thought the Grundfos was a 110 pump, and wired it like that, but the logic circuits never worked, and the pump never moved much water, with almost no pressure. Now I am wondering if I should have been running 220 on it. I'd rather not experiment and blow something up.

    I can get specific model numbers for all 3 of these pumps, if necessary. My main question is if the voltage is completely changeable, if you need to modify something first, or if it's "hard", one way or the other (110 vs. 220).

    Thanks in advance.


  2. #2
    Moderator valveman's Avatar
    Join Date
    Mar 2006
    Lubbock, Texas


    Most jet pumps will work 110 or 220. There is usually a switch or plug in the rear of the motor to move to the 110 or 220 position. Just need smaller wire and breakers with 220 volt. The electronics in the Grundfos MQ are always messing up. Don't bother trying to reuse any of that one.

  3. #3
    In the Trades Texas Wellman's Avatar
    Join Date
    Feb 2010
    SE Texas-Coastal


    Do yourself a favor and take that lowe's pump back. It's not that cheap, but it's really crappy.

    Goulds and Sta-Rite both make pretty good shallow well pumps. They cost more, but they will last way longer. Any good quality pump should have an AO Smith motor, which will work with either 220 or 110. As stated, you are better off with 220, but sometimes 110 will work ok, especially with lower HP pumps like a 1/2 HP.

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