High Amperage Draw from Submersible Pump Motor

Discussion in 'Pumps and Tanks Well Forum & Blog' started by gilster00, Aug 17, 2010.

  1. gilster00

    gilster00 New Member

    Messages:
    3
    Location:
    Exeter, CA
    This is my first post on this forum but I have learned a great deal by reading many of the other topics. Thanks for this great website!

    Okay, here’s my dilemma… My wife and I purchased a home one year ago and our 1.5 hp submersible well pump has recently started blowing the 15A time-delay fuses. This happened for the first time about 2 months ago and has reoccurred 5 or 6 times since then. I have followed the diagnostic tests in the Franklin Electric AIM manual and determined the amperage draw on the motor is too high (possibly bearing failure?). The Max S.F. amperage for this motor is 11.5 and I’m seeing between 11.8A – 12.3A. I had a local pump company come out to verify my diagnosis and they agreed that bearing failure in the motor was likely to blame. The pump/motor also makes a fairly loud humming and vibration when operating. The well still produces great pressure and flow so I’m hoping to be able to just replace the motor and reuse the pump.

    The pump company quoted me $800 in labor to remove and reinstall the pump. This seemed very high to me so I’ve decided to tackle the project myself. The pump is set at 84’ (4 joints of 1.5†galvanized). I’ve thought about replacing the galvanized drop pipe with PVC to allow for easier removal in the future but I hate to throw away the galvanized pipe as it was recently replaced in 2007 by the previous owners. Any suggestions here?

    A friend of mine has a boom truck that is capable of lifting 21 feet and I was planning to make a threaded bail type adapter and steel plate for holding the joints above the casing.

    I consider myself to be a competent do-it-yourselfer but I must admit I’m a little scared to tackle this pump. The thought of dropping the entire assembly concerns me.:eek: Any thoughts, tips, suggestions or encouragement would be greatly appreciated!

    Matt
  2. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    If your buddy has a boom truck he probably can figure out how to hold a piece of pipe while unscrewing the joints. Odd to use steel pipe in 2007 for such a shallow well. To hold pipe as a safety when gluing or screwing, I use a few 6x6 pieces of wood, drill a hole through, split it on a bandsaw, heavy hinge on one end. Heavy clamp on one end makes it a quick action pipe grabber. Using two and leaving the couplers on the lower pipe means its pretty impossible to loose the string. I would probably just cut the pipe as it comes up, instead of going to war on the joints.

    I would'nt try it with with much more than 4 sticks though. Its probably 1.25" pipe, and it deserves a better use as fence posts. Absolutely put it on 160psi poly or dedicated well drop pvc pipe.

    15 amp fuse is pretty small for a 1.5 hp motor, especially with the quality of the fuses I have sometimes found. Go to a 20 amp breaker box. One good fuse now costs as much as a breaker, usually more.

    A pump with a bad bearing from 2007 means you might be pumping the well dry from time to time.

    Use a CRC capacitor start and run control box if its a 3 wire pump - motors run smoother. Next time there is a problem, you and your dog can have the pump out of the well in 5 minutes on poly pipe.

    But remember the 800 bucks includes insurance if the pipe drops. Or get some more bids - this is a simple job in the extreme.

    Also, 1" poly is adequate. Dean Bennet supply sells a poly pipe brass barb that is 1.25" MPT x 1" poly barb. Only place I ever saw that great fitting.
    Last edited: Aug 17, 2010
  3. nhmaster3015

    nhmaster3015 Master Plumber

    Messages:
    836
    Location:
    The granite state
    Drop the new pump down on 1" PE rather than PVC
  4. gilster00

    gilster00 New Member

    Messages:
    3
    Location:
    Exeter, CA
    Here's a little more info on my current setup:

    Pump: 1.5hp Grundfos putting out approx 22 gpm
    Standing H20 Level: 45'
    Pumping H20 Level: same as above
    Pump Setting: 84'
    Well Depth: 134'
    Drop Pipe: 1.5" galvanized
    Pressure Tank: 300 gallon galvanized air type
    Pressure Setting: 40/60

    I don't believe the water level is dropping below the pump since there is a good 30+ feet of head above it. This well is used to irrigate about an acre of lawn and pasture. My theory is the motor bearings are headed south due to over-cycling by the previous owners.

    Can poly drop pipe be utilized with my air type system? If so, how would you install the bleeder valve?

    Thanks again for the help!
  5. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Yes, I do it often. If you are in Exeter, you don't really freeze, and even at the 3000 foot elevation I put my air maker above ground for visual insurance of operation and maintenance. You can design the amount of air coming in by placing the bleeder valve at some appropriate distance from the tank, and the check valve just at the tank with the schrader valve. You can also do a Stainless steel or brass tee anywhere on the drop pipe with 2 brass barbs. I use the rubber 1" bleeder valves. But I think in your climate, moving those joints is safer to above ground.

    Why chance the water drop on a big irrigation run? Static pumping water level changes all the time with seasons and what the neighbors are irrigating in exeter. I would set the pump at 120' as a minimum - no extra head and no extra cost to speak of.

    The big tank reduces cycling, but I would design my zones to keep the pump running at full tilt when irrigation is on.
    In exeter you have some monster irrigation wells, and a temporary draw down of your static water level is very possible. If you have a big orange grove near, count on it. Why not use all the well depth? Pipe is cheap and pumps are not.

    Can you say what was the excessive cycling from previous owners? how many starts a day would you estimate?

    You could add a franklin pumpsaver that shuts down on low water, but the additional pipe will be cheaper than that.

    Maybe you have a method of monitoring your water level easily from the surface installed. If not, I would get all the depth I can.
    Last edited: Aug 17, 2010
  6. gilster00

    gilster00 New Member

    Messages:
    3
    Location:
    Exeter, CA
    You bring up a great point about drawdown... I've sounded the well static and after the pump has been running for just a few minutes. This probably isn't the best draw down test... I'll try checking the water level towards the end of an irrigation cycle on our pasture (about 5 hours) and see where the true pumping water level is.

    The previous owners had the automatic sprinkler valves configured in a way that would cause the pump to cycle on and off frequently. I would estimate 50 starts per day (maybe more).

    Thanks,
    Matt
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