Failing well pump, or somthing else?

Discussion in 'Pumps and Tanks Well Forum & Blog' started by JQ, May 17, 2012.

  1. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    I have a well experiencing some pressure issues under load. Once triggered by the pressure switch, the pump seems to run about 20 seconds or so and then shuts off of its own accord. Checked pressure switch and it is kicking in and out properly at 30/50 PSI. What happens is: Switch triggers pump. Pump runs building pressure, but turns off in 20~30 secs even if it has not hit 50 PSI. Pump sits then turns on again (30 seconds to 2 minutes later). Then off again, then on, etc., until the pressure switch kicks at 50 PSI. Under high water demand, house pressure settles to zero eventually, since pump spends too much time off. I checked electrical and even though the pressure switch contacts are still closed (under 50 PSI), there seems to be no actual current across the switch contacts when the pump has short-cycled itself off -- suggesting that the electrical circuit has been interrupted somewhere other than at the P switch.

    Could this be the pump kicking itself off for some self-protection reason? Anything else in the pump-side electrical circuit that can open up intermittently? How can I diagnose? Thanks for your thoughts!

    Jeff


    Additional info:
    Well 250 ft drill, unknown water level. Gould is a 5SB05422. Two wire system. Preassure tank well-x-trol 32 Gal, verified good membrane and correct preassure charge (however, it was a few pounds low when I bought the house.)
  2. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    The overload in the motor is tripping. It automatically resets in a few minutes after it cools down. Pumps are designed to survive about 7 years of cycling on and off before this happens. "Planned obsolescense", you are going to need a new motor.
  3. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    Hey, thanks for the quick response. Quick and to the point.

    I went back with some better electronics tools and I guess I've confirmed what you are saying. First I double checked that there is no voltage across the closed p-switch when the pump cycles off. Then I snapped an ammeter around one leg of the 220 circuit. After startup the pump settled down (if you can call it that) to about 18-19 amps then switched itself off. When it reset 30 seconds later, it settled to 14 amps, then again off… reset and settled at about 17 amps. Etc. I'm no expert but I'm pretty sure a 1/2 HP pump should be pulling a lot less than that. I'm guessing the pump overload is just a little bit faster than the breaker.

    So my next question is how to size a replacement pump. The current Goulds, according to the stickers on the tank, has lasted 20 years. Not a big statistical sample, but makes me lean toward buying another Goulds. Except the last homeowner put in a couple multi-head showers - so I want to bump up the capacity a bit. Your threads here have made me leery of going constant-pressure. So I'm looking at the 2-wire pumps in the Goulds GS line.

    Right now the pump is 5SB05422 -- which is a 1/2 HP, 2-wire, 5GPM. I'm not interested in running three showers while doing the laundry at the same time, just in getting good brisk pressure for one shower plus incidental concurrent usage. Would 7 to 10 GPM with a corresponding increase in HP do it? Given that I don't know the actual water level, am I safe comparing curves and tables between the current pump and a new to size it? Or do I really need to get a current water measurement?
    Thanks!
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    Not knowing the pumping depth, the next two steps up that will do the same depth as the one you have would be, 7GS07 (3/4HP) or a 10GS10 (1 HP).

    I think a ½ HP is 6 amps max.
  5. masterpumpman

    masterpumpman New Member

    Messages:
    729
    Location:
    Virginia Beach, VA
    If the well supplies enough water you could consider installing a 3/4 hp (Goulds) and a CSV. This will give you a constant pressure with a variable flow demand. A CSV is all mechanical. Try it I promise you'll like it.
  6. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    Csv

    Thanks, yeah, I've been investigating that. I followed your various threads here, and looked elsewhere to follow up. I get the concept, and I'm already mostly sold.

    I understand the CSV wouldn't care, but it seems to me that going too high in capacity would put my well tubing under fairly high preassure a lot of the time. You would also not want to provide too much capacity because you don't want the pump to get ahead of the load and cycle off anyway. So am I correct to think that if I put in a CSV I probably don't want to go overboard on pump? Is the sweet spot somewhere around the preassure / flow rate of your typical long usage events -- like the shower or whatever?

    Or am I missing something about the CSV which would keep the pump from outrunning the load no matter what the pump? Is it just a matter of coordinating the mechanical setting with the pressure switch setting?

    I assume the maximum back pressure that the pump side of the CSV could ever see corresponds to the "shut-off" PSI in the Gould Pumps tables. Is that one way to read those?

    If I read correctly, CSV "constant preassure" is really something like a 5 PSI window determined by the preassure switch settings. If a guys wasn't picky, is there any logic at all to making the window more like 7-10 PSI and taking a more advantage of the pressure tank to avoid pump cycles?

    (Yeah, you can see I've been overthinking it! Thanks for your input.)
  7. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    A CSV will allow you to install a pump with as large a flow rate as you think you may ever need. Then the CSV will make it work like a small pump to match any flow you need all the way down to 1 GPM. The CSV is only limited by the backpressure of the pump, which you correctly state is the shut off head of the pump.

    However, the backpressure is reduced the deeper it is to the static water level in the well. We like to limit the differential pressure across the CSV1A to 125 PSI, with a maximum limit of 150 PSI. This means if the setting of the CSV is 50 PSI, the backpressure is limited to 200 PSI.

    All those pumps listed have a shut off head of about 400’ or 173 PSI. So even if the static water level is 1’ from the surface, the max backpressure will be 173 PSI. With a CSV setting of 50 PSI, this makes the differential pressure 123 PSI, and well within the limits of the CSV1A.

    So you can use a higher GPM pump like the 10 GPM, 1 HP, which can actually produce up to 15 GPM. The CSV will hold a constant pressure when using as little as 1 GPM. The CSV1A has a 7 PSI falloff in pressure from using 15 GPM down to 1 GPM. In other words the CSV will hold 50 PSI steady while using 1 GPM, but will only be able to hold 43 PSI steady when using 15 GPM. But as long as you are using more than 1 GPM, the CSV holds the pressure below the 60 PSI off setting of the pressure switch.

    You still want a 20 PSI bandwidth between on and off for the pressure switch, like 40/60. But the only time you see this swing is when the pump starts of stops. As long as you are using more than 1 GPM, the CSV is in control, there will be NO cycling, and the pressure will only vary from 50 to 43 PSI, depending on the amount you are using at the time.

    You can play with the graphic at this link to better see how the CSV works, because you are over thinking it. :)

    http://www.cyclestopvalves.com/simple/home.php
  8. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    Light bulb is on now, thanks for the link. So the system does incorporate the pressure tank initially, but makes it irrelevant when the water keeps running. If the flow does exceeds the pump capacity, then obviously the pressure will eventually drop down to whatever the pump can actually support. In my case, if the water level is deep I might get actually get a bit less 10-15 with that pump.

    If I'm following the only real things to think about are (1) is my well tubing OK with the pressure load, (2) does the new pump need some kind of cooling shroud to help with low flow, and (3) how much maximum flow I want to support when I choose my pump size. Am I correct that the pump at the bottom of the well sees the full 173 PSI (static head plus house pressure) while the CSV only sees the difference between the top of the well head and the house?

    Does the CSV1A go in the house, just short of the pressure tank, or is it better to place outside at the well head?
  9. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    By George I think you've got it. 173 PSI at the pump. (1) Need 200# poly or 1" SCH 80 which is rated to 225#. (2) A shroud is not needed if the pump is placed above where the water comes into the well. Franklin says 2HP and smaller don't need shrouds for any reason. But I think a shroud is very helpful and always use one if it will fit in the casing. (3) You can use as large a pump as you want, and the CSV will make it work like a small pump when very little water is needed. (4) the CSV can be at the well head or at the house. But it must be placed before any lines tee off the main.
  10. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    I've been checking with contractors on pumps. Any opinions about best brands to pair with a CSV? As I said, I'm pulling out a Goulds which seemed fine to me. But several contractors are saying Goulds "isn't what they used to be" and pushing Berkeley/Sta-Rite. Maybe because that is what they carry…

    Of course, most of them also shift gears to selling me on a Grundfos constant pressure system somewhere in the conversation. Only one of them admitted having heard of a CSV and he had several reasons for dismissing them -- most of which failed my BS detector test.

    That leads me to another question -- are there many contractors who install the things in the North East, or am I going to have to DIY? I'm perfectly comfortable putting in a piece of plumbing myself, so that hardly matters, but I am not so comfortable pulling a 250' well pump on my own. So it would be kind of nice to find someone who'd at least cooperate in the plan.
  11. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    Sorry I let this slide down the list. Yes you can install the CSV yourself if you can't find a reputable pump installer. But there are several reputable installers in the NE that know how and use CSV's every day. Hopefully there is one close to you.
  12. JQ

    JQ New Member

    Messages:
    12
    Location:
    MD
    Thanks for post. I finally ID'd three local guys that deal with them, but only one was comfortable talking about using them in a residential application rather than just in irrigation systems. I'm still contemplating putting in a new Goulds and going CSV right now. I also just learned that Goulds constant pressure controller can use their standard submersible pumps, which I suppose leaves my options open if I ever do want to drop another pile of money and try that out.

    Hey, one other question has been bugging me: Is there any possibility that the reason my old pump is going into thermal overload is that there is a problem with well yield that I don't know about? If the well was going dry would the pump tend to run on a bit before kicking out, or behave just like this? Again, I do get flow and pressure build for 20-40 seconds at a time before it cycles off suddenly. As far as I can tell there is no way of doing a new yield test without pulling the pump anyway, so maybe this is like asking you to read tea-leaves. But I'm a glass-half-empty kind of guy and looking into what else might hit my pocket.
  13. valveman

    valveman Moderator Staff Member

    Messages:
    4,383
    Location:
    Lubbock, Texas
    Your 5 GPM pump will only produce 2-3 gallons in 30-40 seconds. So your well would have to be really dry to not make at least that much water. Usually a pump runs dry after is has been on for a while, not right when it starts. It just takes 30-40 seconds to trip the overload. Sorry :(

    Unless they have another “brand new” type controller, that Goulds constant pressure system requires a three phase motor. So it is a “standard three phase”, not a standard single phase as needed in residential applications. I could be wrong. It could be something so new I haven’t seen it, but I doubt it. And if it is that new, I would be worried about it. Franklin has a single phase VFD, so I wouldn’t be surprised if Goulds hasn’t been working on it.

    Don’t expect many contractors to feel comfortable selling you a disruptive product like the CSV. With a CSV they don’t get to sell you an expensive VFD, or even a large pressure tank. And if they really know how a CSV works, they know it will knock them out of about three more pump sales to you in the next 20 years. Only the most reputable contractors will install a CSV for you and be happy about it.
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