Proper System Design for Well Water Systems

Discussion in 'Pumps and Tanks Well Forum & Blog' started by dhoerl, Jan 14, 2006.

  1. dhoerl

    dhoerl New Member

    Messages:
    13
    Location:
    NJ
    I just bought my first house with a well. While the water tastes great, it appears that the flow to the bath tubs leaves a lot to be desired. I'd like to add a whirlpool tub in the house soon, so I am keeping this in mind (need about 80 gallons for the model I am looking at.)

    Now, the house is plumbed as follows:

    well pump -> 44gallon storage tank (WellXTrol) -> filter -> UV -> water softener -> delivery

    Not knowing well systems at all, it would **seem** that a better way to do this would be this:

    well-> filter -> UV -> water softener -> storage tank -> delivery

    When there is a large demand for water now, the pressure drops across the filters and softener.

    It also occurred to me that if the pump really wants to "see" a storage system right inside the house, that I could add another storage tank after the water softener. The purpose of this would be to "source" water when there is a large demand (high flow faucet at the whirlpool can deliver 50 gallons a minute.)

    Thanks for any pointers or advice.

    David
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    Important thing to note...your 44 gallon tank actually only holds about 14 gallons of water, the rest of the volume is composed of the air (stored energy from the pump). What you really need to know is what is the pump capacity and the well recovery rate. If the well doesn't have enough (fast enough) recovery, then you'll need to reconsider that big tub, or make room for a much more expensive system to store and then pump water for you. With the supply lines you have, I'd be surprised if you can flow more than about 10 gallons/minute (maybe 15). Basically, once you start to fill that thing, you'll have the pump running continuously until it is full. You'll need one hell of a water heater, too. My unprofessional opinion.
  3. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    There are differences of opinion on need for filters on a well, location of filters in the system, and type of filters. You will hear from others.

    How many and what kind of filters are you using?

    If you need a filter, it should be a large filter. The usual 10" cartridge filters are just too small. My preference is something like the 20" long "Big Blue" size cartridge. If you expect to flow more than 15 gallons per minute then you should use two of the Big Blue size filters. You could use two of the 20" long standard diameter filters connected in parallel but the filter life would be less and your total cost of cartridges would be greater.

    Some like the granular filters in a tank that require backwashing. My experience is that they are not as effective in removing small particles.

    Now as to the location of the filters and the tank. If you put the filters and softener after the tank, then the pressure drop across the filters will reduce the pressure available to the system. I put the filters between the pump and the tank with a MANDATORY requirement that there be (1) a relief valve on the inlet of the filter and (2) a differential pressure switch control circuit across the filter that will lock out the pump until the circuit or switch is manually reset. The reason is that submersible pumps usually have very high pressure capability and could fail the filter housings if the filters were plugged and not changed.

    The advantage of putting the filters first is that you end up with the desired pressure in your system and the pump will deal with the filter pressure drop, although with reduced flow.

    Your 50 GPM valve won't deliver unless the pipe is large enough. You should have 1 1/2" copper to deliver 50 GPM and your pump/tank system won't deliver it even with the larger pipe.
  4. Gary Slusser

    Gary Slusser That's all folks!

    Your softener has to be before the UV light or the UV will not work correctly due to hardness scale and iron etc. building up on the quartz sleeve.

    Next to no softener needs a filter before them but, all UV lights do if for nothing more than sanitizing the light. with bleach, and the plumbing past the light when maintenance is done on the light or the power goes off.

    There should never be anything that can block up. like a filter cartridge, between a submersible pump and its controlling pressure switch. A block up can cause serious, read expensive, pump/well problems.

    Plus the fact that pressure tanks don't need any filter and if once a year you drain the tank and flush any dirt out when you check the precharge air pressure in the tank, there never will be enough dirt in the tank to bother yourself with.

    So... well/pump, pressure tank, softener, filter, UV light.

    Gary
    Quality Water Associates
  5. rshackleford

    rshackleford New Member

    Messages:
    284
    Location:
    Eastern Montana (The Bakken)
    try to find some info on the well. find the well log. you may need to contact the state or the board of well drillers. there should be good info on well production.

    you may also want to sample and test the water. one test for minerals and on for bacteria.
  6. dhoerl

    dhoerl New Member

    Messages:
    13
    Location:
    NJ
    Thanks for all the responses...

    First, thanks to all for responding.

    First, more information. Yes, I know I need a big water heater. I am going to recreate a bathroom I had at my last house - 1" water lines from water heater to 2nd floor, 3/4" to the tub faucets, and a 75gallon storage tank.

    The problem I see it is maintaining some "reasonable" pressure when the tub is turned on.

    I have a 3/4 HP pump, but its 200 feet down, so its delivery is a few gallons per minute. What I'm hoping to accomplish is to store enough water in a pressurized storage tank to keep the pressure up.

    WellXTrol has really big tanks - cost is close to $1000, but hey, the tub is going to cost a lot more than that! I can re-plumb the supply lines - I have good access to where the lines run. As jadnashua said, these storage tanks do not really store the amount of water they show as capacity. However, with two of their 120 gallon tanks (WX350), there should be enough capacity to fill the tub (and more).

    Another thought would be to change the approach slightly, and keep the storage tanks at a higher pressure (like 100PSI) then use a pressure regulator (such as is often used in public delivery systems) to maintain a delivery pressure of around 60PSI. I used a high capacity WATTS unit at my last house (cost like $350 back in '99!). Then my system would look like this:

    well-> pressure cutoff switch -> relief valve -> Big Blue filter w/differential pressure switch control circuit -> water softener -> UV -> storage tanks -> [possible pressure regulator to drop 100PSI to 60PSI if needed] -> delivery

    Obviously the optional pressure regulator idea is only feasible of all components can accept a working water pressure of say 100PSI.

    Maybe I would try this in these steps.

    Get the Big Blue filter (or filters), safety pressure switches, and additional 120 gallon storage tank (which would give me 165 tank gallons, or close to 50 gallons of "useable" water).

    See if it delivers enought water. If not, jack the pressure up to 100PSI, and add a pressure regulator. Test again. If this is no good, add an additional storage capacity of 120 gallons. That for sure would do it.

    David

    PS: additional questions:
    a) Regarding the relief valve on the inlet of the filter - does this just bypass the filter or does it vent water (and thus need a drain)? Can you give me a brand/model of a good one to use?

    b) Ditto - make an model for the differential pressure switch control circuit across the filter that will lock out the pump until the circuit or switch is manually reset.
  7. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I don't see any reason for any kind of in line filter be it a 10" or a 20". What is in the well water that these things are going to stop? If there is any dirt or sand in the water the softener will catch that. And it can be backwashed to drain. No cartridges to buy.

    The 120 gallon Well X Trols only hold around 13 gallons of water. If you remove the filter cartridge, does the pressure get better? I assume you have a low flow well. But with the water level being above the pump quite a bit, you should have good water flow and pressure for quite some time during low water use.

    If your going to add all these tanks, you would be better off with a cistern and another pump and tank to pull from the cistern. This way, you could store as much water as you need in the cistern for later use.

    bob...
  8. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The cistern that Bob (speedbump) suggested can be achieved with a polyethylene tank. They come in all sizes and you could put a 200 gallon vertical tank in your basement. I just put four of them in a system that needed to winterize a surface water treatment system. Tank size was limited by the 30" doorway through a stone wall. A single tank is preferred and maximum size depends on what you have space for and can get through the door.

    The objective is to be able to put a lot of water in that tub in a short time.

    I would put all of the required treatment ahead of the storage tank. You don't want to have treatment equipment designed for the occasional high flow. Your existing well pump would be the first stage.

    I don't know whether a filter is required, but if it is required, it should be big enough so you are not changing it frequently. The controls will be simplified a bit compared to a pressurized system.

    Such a system would be:
    Well pump -> treatment -> pressurizing pump -> pressure tank -> water heater -> house->
    The pressure tank is actually off to the side of the system; not "in-line".

    You would need a large enough water heater to fill the tub.

    The pressure tank would be sized to keep the pressure pump from short cycling. I would use a pump in the 30 to 35 GPM range. That is consistent with your 1" water line.

    You need to work out the details of the system to select the controls, pump, treatment, and tank that will all work together.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,240
    Location:
    Cave Creek, Arizona
    tank

    If a 120 gallon tank is going to be full of a 107 gallons of air, then the initial precharge pressure is MUCH too high. The amount of water in the tank will be inversely proportional to the static air charge.
  10. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    We are talking about bladder tanks HJ, and a 120 gallon bladder tank with the proper precharge of 28 lbs. with a 30/50 pressure switch setting will give 13.6 gallons per pump cycle. That's all. If you fill a 120 gallon galvanized tank from zero with no precharge let it shut off at 50 psi and open a faucet until the pressure gets to 30 again you will have let out 13.6 gallons.

    bob...
  11. firebob

    firebob New Member

    Messages:
    10
    Ok here comes my 2 cents. Well it’s more like a pic I just did.

    I am not going to post it as a pic just a link because I don’t want to resize it. To lazy to re scan this pic.

    http://members.cox.net/got_cutco/scan.jpg

    I just want to say that the water softener needs to have a constant water feed with pressure but I did not think about this in till now. So the water softener will need to be moved to the other side of the storage tank and will need to be rated for your flow.

    As said before you will need to run 1†or larger pipe from the holding tank to the faucet. When you look at the water heater remember you will need to look at the recharge rate and the temp of the incoming water. I keep thinking about the water heater and I’m thinking to get the flow you will want you might want to go with 2 and run them parallel.
  12. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    That's not a good idea putting the softener in front of the pressure tank or pressure switch firebob.

    It should be behind the first tank with the pressure switch from the submersible in the well.

    bob...
  13. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Water Delivery and Precharge Pressure

    A 119 gallon bladder tank with 28 psi precharge and 30-50 pressure settings will deliver 35 gallons between 50 and 30 psi.

    119 gallon Tank
    28 psig precharge (42.7 psia)
    30 psig Pump on (44.7 psia)
    50 psig Pump off (64.7 psia)

    Air at 30 psig = 119x42.7 psia/44.7 psia = 113.7 gallons of air.
    119 gal tank - 113.7 gallons of air at 44.7 psia = 5.3 Gallons of water

    Same formula as above gives:
    78.5 gallons of air at 64.7 psia = 40.5 Gallons of water at 50 psig

    40.5 gallons - 5.3 gallons = 35.2 Gallons delivered from 50 to 30 psig

    Ever wonder why they use 119 gallon tanks? It is because most jurisdictions require 120 gallon tanks and larger to be manufactured and certified to ASME pressure vessel code, which costs a lot more.

    And why do they call a 119 gallon tank a WX-350 or some such sillyness? It is a marketing ploy because a 119 gallon tank with 30 psi precharge will supply as much water between 50 and 30 psig as a 350 gallon tank will supply between 50 and 30 if it has ZERO precharge. Of course no one who knows anything about the process would ever operate a non-bladder tank with zero precharge.

    You get the same benefit if you operate a non-bladder tank with 30 psi precharge, but you have to manage or control the air in the tank.
  14. firebob

    firebob New Member

    Messages:
    10
    Speed bump

    Dose a water softener need a constant supply of water? YES or NO

    If you reread my text I think I said I put the water softener in the wrong spot. I never said where to put it.
  15. firebob

    firebob New Member

    Messages:
    10
    Ok I think if we all go back the first post and reread it, I think there will be a simple solution that every one will see.

    Things to be assumed true?
    -Well pump will not put out required amount of water.
    -Water softener and UV light are most likely rated to low for the GMP that is wanted.
    -A water softener needs constant water pressure for back washing.

    I will not repost under this thread. I think too many people with too many different thoughts. I hope you find your solution to your problem dhoerl.
  16. dhoerl

    dhoerl New Member

    Messages:
    13
    Location:
    NJ
    Storage tanks

    I appreciate all the responses. To answer some questions - the filter picks up a lot of red clay, so its definitely needed. The water softener won't pass more than 7 or 8 gpm. Don't know about the UV setup - it might be higher.

    A 75 gallon water heater, with a 38 degree city water feed, will **just** fill the tub in the deep winter. (With in-house storage, and thus warmer water, I expect the well system to do better). 1" copper for cold and hot for most of the run, and 3/4" the rest of the way, and Kohlers curved "C" spout, will fill a 80 gallon Pearl tub in about 3 minutes. So, the flow is more like 27 GPM (the faucet says it can deliver 50 at 60PSI, thus my confusion). 3Min is just fine to fill a tub. [The current house takes 10 min to fill a 4 1/2 foot tub - 1/2" copper everywhere, old valves, etc.]

    As I said before, this is first well for me. I never heard of polyethelene storage tanks - can someone suggest a site to get more info? I assume then that I use some type of water pump, or air pressure pump, to get delivery...

    Thanks again for all the info (which I am trying to sort through :->)

    David
  17. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    David, Send me a private message with your EMail, or read your private messages.
  18. Gary Slusser

    Gary Slusser That's all folks!

    David, the red clay is more liikely to be caused by ferrous iron in the water but, even if it is red clay, it won't hurt most softeners because it will be backwashed out of the resin bed.

    I agree with Firebob that your well system isn't going to be capable of 50 gpm unless you replace the pump with a much larger pump (gpm and hp) and to that you'll probably have to replace the power cable or you'll burn up the one for a 3/4 hp pump.

    You are forgetting the water quality once you get all this watr into the tub. The house has a softener and UV and you won't like the water quality without them but... when you get the price for a softener that can successfully remove hardness, iron and maybe manganese from a 50 gpm flow, you will be shocked for sure BUT... wait til you hear the price for the UV light for a 50 gpm flow!!!

    Also, a pressure (not storage) tank isn't going to get you more water flow; you'll need an atmospheric storage tank and a pump to represurize the water in it. And raising the psi to 100... your pump and plumbing must be capable of the pressure required AND softeners and disposable filter housings are rated at 125 psi and if you have any water hammer at all, you'll exceed that rating and have 50 gpm flowing all over until you discover the problem.

    Me thinks this project needs rethinking.

    Gary
    Quality Water Associates
  19. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Engineering is the process of finding economical solutions that meet the customer's needs. There are solutions to all of the "problems" that have been raised.

    A System That Will Work, with all treatment elements in the existing well pump stream, for which they presumably have adequate capacity:

    Elements in order:
    1. Existing submersible pump
    2. Filter and softener, in order to be determined, protected by relief valve and pressure switch with controls to shut off pump if pressure is exceeded
    3. UV to treat the well pump flow (existing)
    4. Discharge to a polyethylene tank (capacity based on expected demand) at atmospheric pressure, with float switch to control the submersible pump and a float switch to shut off the high flow pump if level in the tank is low.
    5. High volume pump with adequate pressure for the system; probably a multistage centrifugal; with controls to protect the pump if the storage tank runs out of water.
    6. Pressure tank to keep the pump cycle within acceptable limits, based on pump selection.
    7. Water heater to serve peak hour demand

    Questions that must be answered to design the system:
    1. Determine water flow and pressure requirements to meet customer needs
    2. Determine complete treatment requirements based on water tests and customer needs
    3. Water softener backwash and regeneration usually operates off a pressurized system. It will probably require use of water from the pressurized tank for backwash and regeneration, and controls to implement that process.
    4. Verify that there is no requirement to filter after the softener to protect the UV system.
  20. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Sorry Firebob, I should read on instead of just looking at your drawing.

    bob...
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