Water system design - untrusting contractor

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Ali, Sep 2, 2006.

  1. Ali

    Ali New Member

    Messages:
    3
    Water system design advice

    We are currently building a home in Pennsylvania (4 bedrooms, 2.5 bathrooms, dishwasher, washing machine) and our contractor is designing/installing water system on his own (no plumber). As we have learned through this process, he unfortunately likes to cut corners and I am in the dark about this (although learning more and more everyday). I am hoping someone can take the time to review this system to see if it makes sense/am I missing anything.

    Well depth = 240 ft
    Well yield: 9 gpm
    Pump = Sta-Rite ¾ hp 4†stainless steel submersible pump (3-wire)
    80-gallon pressure tank with gauge
    Pressure switch: 40/60 psi
    Control box

    Add-ons:
    Surge arrestor
    Torque arrestor
    Quick-trip protector
    Extra check valve (?)
    Lightning arrestor
    Cycle Stop Valve
    Pump/Motor Protection Device

    My concern is the low yield of the well so we opted for a larger holding tank. Is this the right thing to do? I followed the thread about holding tank size and the calculation determined a 30-gallon tank. This seems like too little storage and pump will be on all the time.

    Is there something we can add to protect the pump if the well goes dry? Our well report stated it went dry after 60-minutes of the yield test (compressed-air method).

    Any other "add-ons" to the system?

    He is dropping the pump next week and I will be there with my checklist. What should go down the well with the pump?

    I was told we will never be able to water our lawn with this well. As long as we have enough water for everyday use, I am ok with that.

    I know this is a lot to ask so any help/advice/direction would be deeply appreciated.
    Last edited: Sep 2, 2006
  2. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    You might consider the Subgard. It goes on top of the pump and protects the motor from running dry. I would recommend doing this now, not later.

    You have more than covered the protection with "Add-ons:
    Surge arrestor
    Torque arrestor
    Quick-trip protector
    Extra check valve (?)
    Lightning arrestor
    Cycle Stop Valve
    Pump/Motor Protection Device"

    The torque arrester is a joke. Surge arrestor, quick trip protector and pump/motor protection device all sound like the same thing to me. The Cycle Stop Valve is a great idea and should be used with a smaller tank. The Pumptec and or the Cycle Sensor are good protection devices.

    bob...
  3. Ali

    Ali New Member

    Messages:
    3
    Thanks for your reply Bob.
    I will look into the Subgard and Pumptec.

    Is there any concern with having an 80-gal pressure tank with a low-yield well (estimated 9gpm)?

    Thanks again.
  4. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    That all depends on your water usage. You might want to look into the Cycle Stop Valve too.

    bob...
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    tank

    A 30 gallon tank would be useless. You need one large enough to handle the water needs of the house for as long as it takes the well to recover, which could be 100, 200, or more of "useful" water. That means either an even larger storage tank, if it has a bladder in it which reduces the effective storage capacity, or an open cistern/tank, that is filled by your well pump and is then pumped into the house with a smaller pump.
  6. Gary Slusser

    Gary Slusser That's all folks!

    Sorry but most plumbers know little to nothing about well water systems, let alone sizing of pumps etc. in a new well, it's not their area of expertise... so your contractor should be relied on. This obviously isn't his first well system... It seems to me you wanted the larger tank, so he included it rather than educate you.

    Your well diameter and number of family members wasn't mentioned.... The diameter of the well has a lot to do with the volume of water you'll have for use. Here in PA you will probably have a 6" well, and they contain 1.47 gallons of water per foot of water above the pump's inlet. That's from the static water level down to the pump. Your pump will probably be set 10-20' off the bottom of the well. As you use water, the 9 gpm recovery rate runs into the well, so until you use over 9 gpm, you haven't reduced the water left in the well above the pump.

    Many people here have 1-4 gpm recovery rates and don't run out of water BUT, you can't run all the water you want to water the lawn anytime you want to without the possibility of running the well dry. That is not good for many reasons.

    The pressure tank does not store 'extra' water, and all the water you use out of the tank must be replaced with water from the well, and it is replaced all at once. A tank is nothing more than a big fat pipe in the plumbing; water comes in and goes out equally. So you can't get more water with a pressurized tank no matter how many gallons it holds; those gallons still must come out of the well.

    With the CSV, you don't need the (a) large tank, and I would tell him to go with a nominal 20 gallon; XT-202 or V60 etc. and save the money. I wouldn't use a torque arrestor, they can cause serious problem years later. I would use cable guards every 10-15' starting just above the pump. No rope either.

    As to protecting the pump, I wouldn't do more than he has suggested unless I used a low pressure safety cut off pressure switch. They cost maybe $10 more than the switch he proposed and work very well. They shut off the second the pump sucks air.

    The only way to increase your stored water capacity is to install an atmospheric (non-pressurized) storage tank and re-pressurization pump, and I would not do that unless absolutely necessary due to the added cost and reduced water quality issues/problems.
  7. Ali

    Ali New Member

    Messages:
    3
    Thank you so much for your replies.

    Gary, you are right, it is a 6-inch well. The house is for a 6-member family. I am glad to hear about the cable guards, I requested them last week. In fact, I requested all the "add on's" to the well not the contractor. Maybe it is a bit overkill. I just want/hope to have this done properly and to have enough water for my family on a daily basis.

    I am still a bit confused about the size of the pressure tank. Some say the bigger the better, others say it is not necessary (small tank with CSV). I failied to mention earlier we will have a 50-gallon hot water tank. Does this change any thoughts?

    The Sta-Rite pump manual states "quick-trip protection" must be installed or the pump warranty is null and void. Does anyone know what this is?

    Also, the contractor originally suggested a 2-wire pump. I thought a 3-wire was better so the control box is in the house should things fail in the future.

    Again, any thoughts are appreciated. I thank you again for your time.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,126
    Location:
    New England
    Having the pump turn on and off quickly and repeatedly will kill it. This should not happen if everything is working right. The short-cycle safety device probably has a minimum off-time setting...thus, even if the pressure called for it, it wouldn't allow the pump to turn on before that minimum delay has passed.

    The size of the WH tank isn't a factor.

    If you go with a CS valve, you don't need a big pressure tank. If you don't, then you need a bigger one than without...how big is determined by the pump, recovery rate, water depth, pump depth. If the pump can't deliver your max flow desired, then you need an atmospheric storage tank and a repressurization pump.
  9. Gary Slusser

    Gary Slusser That's all folks!

    So say we go with a tank that gives you 40 gals of drawdown. That will give the pump more than enough time to cool down after running but, all those gallons must be removed from the well to replenish the tank or you don't have any water to use in the house. The size of the tank is dictated by the required time for the pump motor to cool properly; 60 seconds for up to IIRC a 1 hp and 120 seconds for 1.5 hp and larger to something like 2.5 hp.

    Now to control a pump so it doesn't move all those 40 gallons at once and thereby run the well dry... well that gets difficult and quite expensive while you have more things to eventually need maintenance. IOWs, you can't go to a larger pressure tank and solve a low recovery well situation. But you can go atmospheric storage, and then increase cost and maintenance while creating water quality problems and buy equipment to treat those problems that otherwise you might not have.

    So if you were my Mom etc., I'd be telling you to buy a CSV and nominal 20 gal tank set for like 30/50 psi and have it done with until you find out if there is a water shortage problem; and then to go atmospheric storage done right. Then additionally ASAP, to get a water analysis done and spend some of those saved dollars to buy water treatment equipment and install yourself. :)

    BTW, that water heater is kinda small for a family of 6 unless it is gas or oil fired. And I would have suggested a 2 wire pump (w/grnd); many more control box parts fail and sooner than 2 wire motors; and the cable costs much less than 4 strand.
  10. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    If you did cut into one you wouldn't see much anyway, they are all full of epoxy. The biggest trouble with sand is the guy who drilled the well. If it pumps sand you don't want it. If you do get sand in the pump (not the motor, it's sealed up) and it does't want to start. The start cap motor has more torque, but the two wire motor will go both directions to try to free the pump. The three wire motor will just sit there pulling locked rotor amps until something trips.

    We also sell induction start capacitor run motors which need no start switch, no centrifugal switch or start cap. They work great and pull less amps than their cap start cousins. I love them here because of the ant problem we have with start switches.

    bob...
  11. Raucina

    Raucina Previous member

    Messages:
    515
    All of the franklin start boxes have sealed micro chip switches now, so I dont think the ants would be an issue. Can someone tell me how the motor jogs both ways and then knows which way is the correct direction after all? Never heard that one before.
  12. abikerboy

    abikerboy DIY Senior Member

    Messages:
    202
    Location:
    VA
    The run windings in an induction motor dont care which way the rotor turns. The start windings are what determines direction. If you have an old model electric dryer, try this (and dont laugh until you try); Open the door, and hold the door switch in. Dont press the start button. Turn the drum backwards fast enough to close the centrifugal switch in the motor. The motor will start and run the drum backwards. Dont let it run long in reverse though, because youre also running the blower backwards, and you'll burn out the heaters. If you were to press the start button while the drum were turning backwards (DO NOT DO THIS THOUGH...I speak from experience! Lol!) the drum would come to a stop, shudder back and forth several times, then restart in the right direction. Same principle as the 2 wire pump. I have learned alot by hanging around with a plumber friend lately, and from what Ive learned about sub motors, most 2 wire pump motors have a magnetic start switch (biac) epoxied inside of the windings. If the motor is bound up, the rapid opening and closing of this switch causes the motor to shudder back and forth, and eventually will jog the bind free, and then the start windings will start the motor running in the right direction. To get an idea of this, watch the turntable in your microwave oven. The motor in the turntables are very low torque, and dont need start windings. When you use the microwave one time, the turntable may turn clockwise, yet the next time you use it, it may turn counter clockwise. This is the same effect that you get when the biac switch opens the start windings in a bound up pump motor. Remember the old plug in electric clocks? They used a mechanical ratchet device to start the motor in the right direction. You could force an old clock motor backwards, breaking the plastic pawl off the motor, and then you could unplug the clock, plug it back in, and it would run backwards. See the next post in the thread before replying please;
    Last edited: Sep 6, 2006
  13. abikerboy

    abikerboy DIY Senior Member

    Messages:
    202
    Location:
    VA
    Continuation of my last post;

    The exception to my last post on motor direction is a shaded pole induction motor, like what you would find in your bathroom vent fan. No start windings, start switch. No capacitor. The two poles of the motor are actually designed to force the magnetic flux around the rotor in a certain direction, (it would take a while to explain the actual theories behind this) and the design of the ferrous inserts molded into the rotor cause the motor to run in the direction that it was designed to run in. You can remove the endcaps of a shaded pole motor, turn the field housing end for end, put it back together, and reverse the direction of the motor.
    1 person likes this.
  14. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I was referring to the Jet an Pool pump motor for the ant problem. We spend half our time flicking start points and pressure switch points to burn the little critters up so the switch can start doing what it was intended to do.

    bob...
  15. Raucina

    Raucina Previous member

    Messages:
    515
    Thanks for the interesting motor information - I thought there had to be something inside the epoxy to cause the jogging. Looking at the catalogues, it seems the 2 wire pumps stop at around 1.5 HP - and there is a foot note that says do not use in water with grit or sand or mineral deposits - so that pretty much rules out use in my area...

    starting switches are a constant source of motor failures indeed, be it ants or broken springs - seems a great spot to go all electronic or to seal it up - engineered failure again.

    I have experience with Grundfos radiant circulating pumps "impedence protected" they can sit under power, not spinning for months. Open the end cap [wet rotor] and spin the shaft with the slot for that purpose - it breaks free and its good for another year. What exactly IS impedence protected? Is that a shaded pole type of motor?
  16. abikerboy

    abikerboy DIY Senior Member

    Messages:
    202
    Location:
    VA
    Youre welcome Raucina. There's not much here that I am smart enough to answer, but I must admit when something like this that I do know a small amount about appears before me, I can actually even feel my head swelling with ego! Lol!! Anyway, an impedance protected motor is designed so that the winding will not draw excessive energy when the rotor locks. (impedance is the resistance of the windings) They will get warmer than normal, but you can leave power turned on to them indefinately, even with a locked rotor, and they will not draw enough current to burn out. And yes, shaded pole motors are impedance protected. There may be some shaded pole motors which arent, but all of them that I have ever seen are. Because there are no starting components or starter windings at all, and no capacitors on most shaded pole motors, the windings will never draw but a very small amount more energy than normal even with a locked rotor. The insulation on the windings is designed to deal with what little bit of extra heat does exist under a locked condition, and as you noted, they can be locked for a long time with power on, and not suffer any severe damage.
    Last edited: Sep 7, 2006
  17. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    A horse and a half motor should be pulling 4 to 5 times the running amps which should be around 11.5 for the 1.5hp. So I would be looking for more like 50 amps at locked rotor. Maybe the generator doesn't have the oomph to do the job.

    If this pump has been in for this long a time, it may be so gummed up that it will never start again.

    About reusing it, I guess it would just depend on it's condition. For my money I would replace it, but I don't spend as much on a new one as the next guy.

    bob...
  18. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    That's the beauty of a two wire motor. If it doesn't work and you have two thirty going down to it. It's gotta come out. No further testing required.

    bob...
  19. abikerboy

    abikerboy DIY Senior Member

    Messages:
    202
    Location:
    VA
    Had dinner with a well driller friend of mine today, and since I am currently helping a friend with some cunstruction work, I decided to ask some questions. His theory on 2 wire v/s 3 wire pumps, a 1 hp pump motor will only produce 1 hp maximum, and it doesnt matter whether it is 2 wire or 3 wire. He says that he uses 2 wire up to a certain depth (cant remember his limits), and after that depth, he uses 3 wire. He says that with an excess amount of drop cable, the line loss voltage becomes too low for a reliable start, and the 3 wire pump puts the high current draw above ground instead of forcing it to travel through hundreds of feet of cable to reach the pump below ground. HE says that if you look at any sub pump motor table, after a certain hp rating, they are all 3 wire anyway because the high hp motors are for deeper well use. Also have an interesting post on here about cycle stop valves.
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