Please critique my pump/pipe plans

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by DStyduhar, Aug 27, 2018.

  1. DStyduhar

    DStyduhar Member

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    Aug 21, 2018
    Location:
    Reidsville NC
    Hey guys,

    Spent a bit trying to get my ideas down in a drawing. Yes, this is MS paint so go easy on me, but please critique the heck of it. One thing not shown is a CSV out by the well before the hydrant. Ran out of steam and beer to add that in :)

    1. I'm not sure how to split off my main water line for the shop? Another pressure tank out there?

    2. I'm working on calculating my TDH but not sure how many GPM I should really use? I added up all the fixtures and GPM requirements but it's a stretch to assume all of them will be in use at one time. How would you size the pump for a setup like this? More than one pump?

    thanks in advance,

    Drew
     

    Attached Files:

    Last edited: Aug 27, 2018
  2. Reach4

    Reach4 Well-Known Member

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    Attachment worked.

    7 or 10 gallons is usually good for a normal house. If you are doing more than incidental irrigation, things change.

    Probably 7 gpm 1/2 HP or 10 gpm 1/2 HP or 10 gpm 3/4 HP.

    Normally just the one pressure tank.
     
    Last edited: Aug 27, 2018
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  4. DStyduhar

    DStyduhar Member

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    Aug 21, 2018
    Location:
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    I have been screwing with the attachment and it looks like crap. Is there a limit to file size? The picture is huge on my computer but this doesn't translate to what Im seeing in the thread.

    So even with all the potential gpm draw, you still only think 10gpm or so? I state 3gpm for a rotating impact sprinkler next to the shop which will be used to water our small .1 acre sorghum plot. Maybe I should double that figure.

    Without a pressure tank in the garage, how would the shop water stay pressurized? Or are you saying I should tee off to the shop AFTER the pressure tank?
     
    Last edited: Aug 27, 2018
  5. Reach4

    Reach4 Well-Known Member

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    I think it is 199.99 kB or 200kB. This is in addition to the 800 pixels max in either direction

    To make the picture bigger, the viewer can click on the picture, and it gets as big as it goes. Right now if the reader clicks on your picture, it is readable.

    To make a picture you uploaded look bigger on the existing post inline without clicking the picture,
    click Edit
    click More Options
    click Full Image
    click Save Changes.
     
  6. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
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    Lubbock, Texas
    No you don't need another pressure tank in the other building. Just use large enough pipe between the buildings to reduce the friction loss. But with two buildings I would use the 10 gallon size tank in the first house while using a CSV at the well. I don't understand the 250 gallon tank and hand pump when you will have 50 PSI constant in the house already? Might be good for power out conditions, but need to make sure the water gets used regularly to keep the 250 gallon tank from becoming stale or growing green stuff.

    Of course a CSV is more useful the more water used, like for irrigation. But he CSV is still very useful for house use. It allows a much smaller pressure tank and delivers constant pressure to the house. Unless you take sponge baths you will like the constant pressure in the house. The longer pump run times makes the pump and tank last much longer than when cycling on and off. Worst case might add a dollar or two to the electric bill every month, which is cheap insurance and will make your pump last 3-4 times longer than normal.
     
    Last edited: Aug 28, 2018
  7. DStyduhar

    DStyduhar Member

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    Aug 21, 2018
    Location:
    Reidsville NC
    Valveman,

    We had a crappy power grid where I'm at and lose power multiple times a year, sometimes for a few days. I want to have something as a backup and not just rely on a gas generator.

    I'm still a newb here but in order to calculate the TDH, I need to know the friction loss of the pipe/fittings. To know the friction loss of the pipe/fittings, I need to know the GPM requirement. Is this wrong?

    You could add a million bathrooms/fixtures to your house but it doesn't mean just because they all add up to 30gpm that you need that big of a pump. Can someone explain how I would determine my estimated gpm usage based on that illustration? BTW, I plan to use 1" poly throughout and similar ID copper in the basement.

    thanks!

    Drew
     
  8. Reach4

    Reach4 Well-Known Member

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  9. DStyduhar

    DStyduhar Member

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    Reidsville NC
    Reach (and others), can you explain what is going on in your mind when you suggest 7? How do you come to that number? The house has 12gpm max and the shop will have 6gpm. Is it a feel thing?
     
  10. Reach4

    Reach4 Well-Known Member

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    Some softeners have a peak flow reading that resets each month. That is usually under 8 gpm for most. For me it is 6.x gpm.

    That doesn't mean that you can't plug in 10 or 12 gpm for selecting your pipe. No problem with a pipe being bigger than you need.
     
  11. valveman

    valveman Cary Austin Staff Member

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    5 GPM is my rule of thumb for a regular house. Like you say it is rare that every faucet would be on at one time. 5 GPM usually covers all the things that will be on at the same time. My rule of thumb comes from experience. I do systems with 5 houses using a 25 GPM pump, and so on. 5 GPM actually covers peak demands. Larger cities only use 1.5 GPM per connection as a required flow rate.

    If you are using your 250 gallon tank for storage when the power is off, that is a good idea. The hand pump works, or you can use a 12V pump like in an RV, as it will build some pressure and let you flush toilets and take showers.

    PS; Any irrigation requirements should be added to the 5 GPM the house will need.
     
    Last edited: Aug 28, 2018
  12. DStyduhar

    DStyduhar Member

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    Valveman, I'm trying to visualize this. So, with a "typical" well setup the TDH numbers are run assuming the water simply goes from the pump to the pressure tank. In my case it goes from the pump to the pressure tank but tees off and goes another 250' feet. All the TDH calculation examples I have found online show the first example. Should this difference in my setup be factored in when calculating TDH? Hope that makes sense.

    thanks,

    Drew
     
  13. Reach4

    Reach4 Well-Known Member

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    Drew, the TDH curves tell the story. However pump makers also present that info in tables that are easier for most to follow. Here is an example for three 7 gpm pumps: [​IMG]
     
  14. DStyduhar

    DStyduhar Member

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    Aug 21, 2018
    Location:
    Reidsville NC
    Reach,

    I am using the following formula for TDH and running the numbers for 7 and 10gpm.

    Total Dynamic Head (TDH) = Pumping lift + elevation change + operating pressure + friction loss

    An example from my comment above would be the elevation change. There is zero elevation change from pump to pressure tank but from pressure tank to my garage, it prob drops 5 feet. I know 5 isn't much in terms of TDH but would I put a zero or five here? Error to worst case (zero)?
     
  15. Reach4

    Reach4 Well-Known Member

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    From the pressure tank to the garage would be a -5 ft (minus 5). That might come close to canceling out the friction loss for that leg.
     
  16. DStyduhar

    DStyduhar Member

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    Hey Reach,

    See my TDH for both 7GPM and 10GPM using 1" poly. I will be changing to copper in the basement and then back to poly going to the shop. I treated the copper run with same friction loss as poly. Please let me know if something looks off in my calculations.

    Looking at the chart you provided for 7gpm, looks like a 3/4 pump at that head will result in ~5gpm. Do you have any 10gpm charts?

    Questions:

    1. I only measured friction loss of drop pipe down to water, not down the well all the way to the pump. OK?

    2. Should my house pressure be 60? Or should I choose something more average like 50?

    3. A site I found has 3 linear feet as equivalent for a stand 90 degree 1". Does this sound reasonable?

    thanks,

    Drew
     

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    • TDH.png
      TDH.png
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  17. Reach4

    Reach4 Well-Known Member

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    See http://www.blumenauerpumps.com/groundwater/SP4performanceSpec.pdf

    That distance counts, but not much. We are talking about a fairly short distance there.

    You want to keep at least 30. The pressure at the pressure tank would typically move between 40 and 60 if you set up the pressure switch that way.
    It does not set off my BS detector.

    Note that PEX, SIDR poly, and type L copper all have different inside diameters. It depends on how rigorous/obsessive you want to be. You are on a roll, so you will probably want to seek out those numbers.
     
  18. valveman

    valveman Cary Austin Staff Member

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    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    The distance and pressure loss after the pressure tank needs to be considered when setting the pressure switch and sizing the pump. If after the pressure tank say you have 10 PSI of friction loss and/or elevation increase, then you need to add 10 PSI to the pressure switch setting and to the TDH of the pump. When using a 40/60 switch you can figure 50 PSI average to add to the TDH for the pump. So instead of 40/60, now you need 50/70 on the switch for an average 60 PSI (138') to add to the TDH required by the pump.
     
  19. DStyduhar

    DStyduhar Member

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    Location:
    Reidsville NC
    Valveman - two things here.

    1. I have never seen a TDH calculation where someone calculates the friction loss through the copper/pex piping (after pressure tank) going to their faucets, tub, etc.

    2. My last question was sort of confusing. I was asking about the leg that goes to the shop. It tees off right BEFORE the pressure tank.

    Maybe Im just confusing myself.... :)

    Drew
     
  20. Reach4

    Reach4 Well-Known Member

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    Location:
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    Pressure drop calculations in water pipes are common. Try this in a search engine: pipe pressure drop calculations elbow
    However most of them are carried out in units other than head. But note that head and psi are just different units for an equivalent thing.

    So if you are doing well calculations and then keep going, you could stay with the units you are using (head), or you could switch over units. If you are a well person, it seems natural enough to stay with the units you commonly use. You could switch over to pascals or N/m² or bar or atm or inches of mercury. Feet of water and inches of water are also measurements of pressure. The pressure of gas to a natural gas furnace is usually stated to be about a 6 inches of water column.
     
  21. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
    Location:
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    At 10 GPM your 1" copper will lose 3.52 PSI per hundred feet and 1 1/4" copper would only lose 1.18 PSI per 100 feet. When using less than 10 GPM there will be much less friction loss. So even with 1" copper running 250' you would only lose 8.8 PSI after the pressure tank.
     
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