3yr old SS pump motor corroded AGAIN

Discussion in 'Pumps and Tanks Well Forum & Blog' started by blown, Apr 11, 2011.

  1. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    Some of you may remember that 3yrs ago I pulled my 3-year-old Franklin 4" submersible pump out of the ground and found that the stainless case was eaten away like a battery anode.

    http://www.terrylove.com/forums/sho...ump-motor-case-corroded-so-badly-it-seized-up

    I replaced it with a same-sized Grundfos (I actually bought it from speed_bump here on the board). Wouldn't you know it; I turned it on for the first time this spring and no water. I eventually pulled it out and it is also corroded away. I still have to clean off the black sulfur gunk off it, but here are the pics I took:


    blown_3.jpg

    blown_1.jpg

    blown_2.jpg


    I'm not sure how the thing even worked up until the end of last season, but the biggest question is:

    HOW DO I KEEP THIS FROM HAPPENING AGAIN??

    I enjoy do-it-yourself projects. I enjoy saving money. I enjoy working outdoors and building things. But I don't EVER want to see the inside of this well again in my life.

    Can anybody tell me why this is happening and how to stop it??
    Last edited by a moderator: Apr 12, 2011
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,922
    Location:
    NW Ontario, Canada
    My guess is there are ground loop currents causing the corrosion. Is the pump in a metal well casing or in a rock bore? Is the casing grounded? Describe the service feed and grounding. How far from the transformer on the pole to the service entrance? what gauge of wire feeding to the main panel?
  3. thassler

    thassler New Member

    Messages:
    106
    Location:
    Tennessee
  4. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    The well casing is PVC and as such is not grounded.

    I'm not sure how to descibe the service feed. The wiring is all underground. There are no transformers on poles around here. There a couple of big boxes on the ground near the street (and close to my well) but I dont' know if they are for electrical or communications. They are about 100ft from my electrical panel.

    As far as gauge of wire feeding into the panel in the basement, I would have to measure it I guess but it's BIG. Like ~1/2" diameter if I remember correctly. I have a 200A panel.

    I can take pictures of things if it would help. Just LMK what you want to see.
  5. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    The hole might be a lightening strike. Must be stray current. Is this a 2 wire or three wire pump and is there a ground wire? What voltage? What is your waters PH?

    You might want to move this over to electrical also.
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,922
    Location:
    NW Ontario, Canada
    The pitting and the downward flowing stain under the pits suggest that there may be electron flow. The hole at the bottom looks like it could be lightning damage.

    Is there a clorine treatment system on this well?
  7. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    This is a 2-wire pump, 240V. There are 3 wires total which I believe 2 are hot and the 3rd is return? I will check in the box when I get home tonight or tomorrow to make sure I'm not telling a lie.

    I had the water tested 3yrs ago and it was 7.3. That was not water that was pumped out; that was taken just from the top of the water table.

    There is definitely lots of sulfur in the water; you can smell it when the sprinklers come on and it leaves a residue on everything after a while.
    No chlorine treatment. This well is connected directly to a lawn irrigation system. Not used for drinking or anything else.
  8. WellWaterProducts

    WellWaterProducts In the trades

    Messages:
    126
    Location:
    Northwood NH
    How is the pump cycling. I've seen abrasion on pump motors as well.
  9. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    The pump feeds sprinklers (~13 zones) that run every 2-6 days depending on the weather.

    The pump does not feed a storage tank or anything else. Just the sprinklers.

    Also keep in mind the well case is PVC.

    Does that answer your question?
  10. WellWaterProducts

    WellWaterProducts In the trades

    Messages:
    126
    Location:
    Northwood NH
    No pressure switch then? What starts the pump?
  11. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    No pressure switch.
  12. WellWaterProducts

    WellWaterProducts In the trades

    Messages:
    126
    Location:
    Northwood NH
    Is it possible that no water is flowing past the motor?
  13. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    I guess it's possible. The well always produced very well up to when I shut it off last fall.
  14. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Now I am confused. In electrical you show us the pump HEAD looking shiny and brand new!

    If that is the one from the well, you strictly have an ELECTRICAL corrosion issue.

    What is the pump head condition from the ugly motor?
    Last edited: Apr 13, 2011
  15. DonL

    DonL Banned

    Messages:
    3,979
    Location:
    Houston, TX
    Hello Group,

    And I agree with BallValve "The hole might be a lightening strike" , That is if you did not make the Hole, Too take a look See.

    The Hole Does not even look Corroded, That much. If it was a lightening strike, I would think that the wire would be discolored also.

    DonL
  16. blown

    blown Engineer

    Messages:
    77
    Location:
    Wichita KS
    Yes, that's the same pump that came off of both motors and still looks nice and shiny, no signs of corrosion.
  17. WellWaterProducts

    WellWaterProducts In the trades

    Messages:
    126
    Location:
    Northwood NH
  18. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    If they have not told you in electrical, I would install a so called equipotential grounding grid at the well head, or at least some ground rods, which you can lay horizontally in a 1 or 2' deep trench, and bond your ground wire from the pump to it correctly.

    Check your incoming and running voltage also at the pump.
  19. DonL

    DonL Banned

    Messages:
    3,979
    Location:
    Houston, TX
    Hello Group,

    Nothing like good old steal pipes as a well casing, Getting a Ground is not a problem.
    PVC just don't work with lightning strikes. A lightning protector may be the answer, For a PVC pipe.
    You still need a good Ground for the power dissipation, when you get a strike.

    DonL
    Last edited: Apr 14, 2011
  20. valveman

    valveman Moderator Staff Member

    Messages:
    4,426
    Location:
    Lubbock, Texas
    Lightning usually makes a hole in the top of the windings, not the bottom. This is not always true but a hole by the thrust bearing is usually not from lightning. I am also guessing a ground current issue. I have seen where the water heater was not wired properly and caused this kind of damage to the pump/motor. Ground currents are hard to find, might just want to add some more grounds to everything.
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