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Submersible Pump Overloading in Cold Weather

Discussion in 'Electronic Repair' started by Mark & Mary Ann Weiss, Jan 25, 2005.

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  1. I'm looking for input on whether oil-filled motor start capacitors can
    develop a 'cold failure' mode. The situation is as follows:

    We started having a consistent problem with our submersible well pump since
    the temperatures have started dipping to 0ºF this winter.
    The first time it happened was the first week of December, when the
    temperature hit zero. The water pressure in the house dropped to a trickle
    and the tank pressure gauge was down to 10PSI range but the pump was not
    running. After some troubleshooting, I hit the 'overload reset' and the pump
    started up and all
    was well... until January, when the temperature hit zero again. Then the
    same scenario--no water pressure, go down and reset the pump controller and
    pump starts up. All is well for the rest of the week. Until the next time
    the temp hit zero or below.
    There is a clear pattern. The pump overload cutout occurs when the
    temperature reaches zero or below.
    The pump is submerged some 220' below ground surface. The lines leading from
    the well casing is 4' below surface of ground all the way to the house. That
    should be below the frost line. And since 1973, we have had much colder
    winters and no problems with the pump overloading and shutting down like
    this.
    Once I reset the controller, the pump kicks on and refills the Extrol
    pressure tank at the usual rate of speed and reaches the upper cutoff
    pressure and shuts off until needed again. It usually stays working until
    the next bought of cold weather.
    The controller box is in the cellar, which normally maintains around 66ºF,
    but on the very cold nights gets down to 60ºF. I'm wondering if the
    capacitors' electrical characteristics can change that much because of
    temperature if the cap is marginal and on the verge of failure.
    I'm at a loss as to what the cause of this behavior is. I doubt that the
    pipes at 4' depth are freezing (and if they were, we would not get water at
    all once reset), but the overloads only happen on the coldest nights of the
    season, and with predictable consistency.
    The last time this happened, I had more difficulty starting the pump. I
    pressed the reset, but 5 seconds later, I heard a click and nothing
    happened. I could not reset it for another two minutes, but after that time
    elapsed, the reset button finally clicked in and I heard water rushing in
    though the main pipe.
    Does anyone have another idea as to what could be causing the overloads on
    cold nights? Is it a failing start capacitor?


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  2. rijo1

    rijo1 Guest

    Depending on whether your pump is a Goulds or Red Jacket or other brand , you
    may very well need to replace the relay contactor . The capacitor is other good
    or bad and is almost never border line unless it is leaking . Also check all
    wiring connections as well as fuses if fuses are used for loose connections . By
    the way , the start capacitor should be a electrolytic capacitor what is not oil
    filled . Oil filled caps. are used as run capacitors . Hope this helps .
     
  3. Hi,

    Thanks for the quick response.
    The pump is actually a Sears Best model, sold through, you guessed it,
    Sears.
    From what I can tell, the control box contains two capacitors and some sort
    of circuit breaker (the kind with a big red pushbutton). Good to note about
    the electrolytic. Being 20 years in service, it COULD just be drying out.
    We have had a few incidents in recent years where the circuit breaker
    feeding this box has literally detached itself from the buss. (The face
    panel has been off the main breaker box as this place has been eternally
    under construction, and the stiff #10AWG wire would tension against it,
    causing it to sometimes pull out.) I'll check the connections and tighten if
    necessary at that breaker.
    There are a secondary pair of fuses in a small fuse box just above the well
    pump controller. These are snugly installed.
    One thing concerns me though, although this has been so for some 32 years: I
    see no evidence of an earth ground on the pump controller. The only wiring
    between the little fusebox above it and itself is the two 220vac legs. The
    earth ground stops at the fuse box and does not follow to the pump
    controller. I'm tempted to add one, just for good measure.
    But the electrolytic start cap now raises my suspicions as a culprit.
    Keeping in mind here that this seems to be a cold weather problem, the
    potential of a loose electrical connection that fails when cold is something
    I did not think of before.


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  4. Given the age of the equipment IMHO change out the start cap, probably the
    most practical approach would be to go through in that manner. Start with
    the cap (which would cause exactly those problems). Secondly the relay,
    assuming you have checked all connections.
     
  5. rijo1

    rijo1 Guest

    One more thing to do is check the amp draw while the pump is running with an AMP
    Probe to see if the pump is drawing more amps than it is supposed to . If that
    is the case then the pump is worn badly .
     
  6. So far, (I haven't checked with an ammeter yet) today the pump failed to
    start (and it's 27ºF) and when I pressed reset, I noted that the house
    lights dimmed until the reset overload protector tripped (with quite an
    audible 'pop' like when you short circuit 110vac). I had to make three
    attempts to get the pump to finally start.
    I visually-inspected the box, having disassembled the covers and the plug in
    module. It contains a bakelight-jacketed round start capacitor, and a metal
    can oil-filled run cap, in addition to the pushbutton and a relay, sealed in
    a bakelight case. All look as they did when new. No evidence of leaking
    electrolyte, no rust, corrosion or burn marks.

    My next move will be to buy replacement capacitors and see what that
    accomplishes, if any.
    I am worried that the pump, now 20 years old, just may BE worn out.
    (Bearings? Sludge buildup?) It is January here, and the plastic pipe going
    down the well would crack at these temperatures if subjected to flexing
    necessary to pull the pump. The last time I did this it was in the mid 50ºF
    range and we managed okay. But it is January with more snow on the way.


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  7. Guest

    greetings,

    I went through a similar process a few years ago with my well pump
    (Franklin 1-1/2 HP).
    In addition to the capacitors and the overload breaker in the control
    box, there was a
    start relay that had developed an open winding. It would stay in the
    "start" position
    drawing ~11 amps for about 10 seconds until the overload breaker popped.

    This happened shortly after an electrical storm where there was a strike
    within a quarter
    mile. I didn't see any obvious damage to the relay - no burn/scorch
    marks or anything.
    Very fine gauge wire is used to wind the relay coil, so it may have
    opened up just because.
    Your's may have developed a temperature-dependent fault.

    hope that helps,
    L
     
  8. I was going through this same issue - Thanks for helping to clear my
    confusion!!

    :D
     
  9. I was going through this same issue - Thanks for helping to clear my
    confusion!!

    :D
    Posted via http://www.Ugroups.com
    Your Free Web Gateway to the most popular discussion groups on Usenet
     
  10. NSM

    NSM Guest

    If you have a clamp ammeter, try measuring the amps on each leg while
    starting.

    N
     
  11. Very good suggestion. I had no idea about that relay and the possible
    failure modes. I guess the best thing to do is replace the start cap and
    that relay both and see if it cures the problem.

    Still, at 20 years of age, even though it IS stainless steel, I wonder how
    much life is left in the actual pump.


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  12. I was planning to insert an AC VOM ammeter, but I don't have anything that
    goes up to at least 50 amps to be safe for the surge starting current. And
    even so, if the run current is ~7amps, what should the starting surge
    current rise to? What's normal and what's too much?


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION • FILM SCANNING • DVD MASTERING • AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  13. NSM

    NSM Guest

    A good rule of thumb is 6 times the run current.

    Replacing the caps and the relay has to be much cheaper than replacing the
    pump, and if it IS the pump the new parts may be worth keeping anyway. Do
    make sure the thing is grounded, although if you have an all metal plumbing
    system that's pretty much covered. I'm a great believer in bonding all metal
    together - prevents much nastiness.

    N
     
  14. Kim Clay

    Kim Clay Guest

    First choice would be that electrolytic start cap. Its the weakest link
    in the system & its cheap to replace.

    from a previous post: "The controller box is in the cellar, which
    normally maintains around 66ºF, but on the very cold nights gets down to
    60ºF. I'm wondering if the capacitors' electrical characteristics can
    change that much because of temperature if the cap is marginal and on
    the verge of failure."
    Yes, it can change with temperature. If it changes from "just enough"
    capacitance at 66° to "almost enough" capacitance at 60° the pump will
    not start.
    At 20 years replacing the start cap is a good idea even if it has not
    failed (yet). The oil-filled run cap may last forever.
    The start relay is fairly robust but might be going intermittent.
    Replacing it now will not be a bad idea since it has had many starts
    under its belt in those 20 years.

    The same goes for the "reset overload protector". It seems to be
    functioning correctly at the moment because it is tripping & you can
    reset it - sometimes resulting in normal operation of pump. The typical
    overload protector is a thermal device which "pops" when it gets hot
    (due to overcurrent). Typical failure is tripping at a lower than rated
    current due to aging & contact resistance. You may want to consider
    replacing it even if it is not the root cause of your problem at the
    moment (after you get the system back in operation) just to prevent
    future problems.

    How much life is left in the pump motor? It is hard to tell but each
    time it trips the overload protector you are overloading the motor!
    Typically the motor internal windings/connections get very hot quickly
    if it does not start correctly. If given 5-10 minutes between each
    attempted start they will have a chance to cool down due to thermal
    conduction to the water. Repeated rapid attempts to start which result
    in the overload tripping are bad. It the windings are already hot from a
    previous overload & another attempt is started immediately they get even
    hotter. Not good.

    Enough for now... That missing ground does seems to need attention...
    Please be careful :)

    Kim
     
  15. Jim Adney

    Jim Adney Guest

    You could try putting some kind of small heat source near the
    controller and capacitor, just to test your theory. Just putting a
    cardboard box around it, with a 15W bulb in there would be enough to
    keep it 20F warmer.

    Don't get carried away. You don't want to do anything that will start
    a fire.

    -
     
  16. Thanks for that rule of thumb. No wonder our old 5kW genset used to stall
    out when the pump kicked on, or tried to.

    Well, I've gone through all the connections, contacts and ground checks
    earlier this evening.
    Took out the main Cutler-Hammer breaker and, using a longnose pliers,
    squeezed the spring clips that hold the clamp on contacts together a little
    tighter and reinstalled. Then I cut up some strips of rough cardboard and
    used them to burnish the pressure switch contacts while pressing the
    contacts closed with a piece of wooden shim material. Next, I installed a
    ground wire from the secondary fuse box above the pump controller and
    connected it to the controller cabinet where the 3rd wire from the lightning
    arrestor was bolted.
    Then I powered everything up and used a piece of wood to push the pressure
    switch contacts closed. Pump kicked on without any issues. Switched it on
    and off a few times and the pump started every time. Pressure rapidly
    reached 100PSI on the tank gauge and then water started gushing all over me
    and the pressure switch I was operating--the pressure relief valve let go
    without warning. It appears that the pump is quite capable of filling the
    tank and raising the pressure to danger levels in a matter of seconds. Next,
    I opened a spigot for the outdoor hose. Let the pressure drop to 40PSI and
    heard the pressure switch close. Closed the valve and watched as the
    pressure came back up to 59PSI and shut off. Repeated process about a dozen
    times. Pump never failed to start up each time. Pressure builds from 40 to
    59 in about 15 seconds.
    I guess we'll see how it goes over the next month. If no more problems, I'll
    consider that it was a bad connection somewhere. Perhaps one leg of 220 was
    intermittent and the pump wasn't getting enough juice to kick over, causing
    the other leg to overload and shut down. Hopefully that's all it was. Time
    will tell!


    --
    Take care,

    Mark & Mary Ann Weiss

    VIDEO PRODUCTION • FILM SCANNING • DVD MASTERING • AUDIO RESTORATION
    Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
    Business sites at:
    www.dv-clips.com
    www.mwcomms.com
    www.adventuresinanimemusic.com
    -
     
  17. NSM

    NSM Guest

    ....

    Glad to hear it. I can't recall any case I ever heard where the problem was
    caused by too much grounding. But the story about the bath, the metal coated
    wallboard and the chrome towel rail would make your blood run cold.
     
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