[NA]Hydrodynamics[NA]

Let'sgoflying!

Touchdown! Greaser!
Joined
Feb 23, 2005
Messages
20,315
Location
west Texas
Display Name

Display name:
Dave Taylor
Anyone here a genius at household water works? I want to chat about my well, pressures and flows, fixing a long standing issue with a low performing system. None of the experts can agree.
 
Anyone here a genius at household water works? I want to chat about my well, pressures and flows, fixing a long standing issue with a low performing system. None of the experts can agree.

I had some well issues to deal with, not an expert, but I managed to get the job done.... What issues do you have?
 
I'll try to help, too.

Depth
Pump HP
Incoming line diameter
Incoming line material
Pressure Tank Size
ON/OFF Pressure setting on switch?
 
thanks.
let me work on getting together a diagram and stats

The problem is low flow and pressure mainly the shower, when other items are drawing.
 
thanks.
let me work on getting together a diagram and stats

The problem is low flow and pressure mainly the shower, when other items are drawing.

Can you build an elevated tank? Usually a couple hundred gallons is enough as long as the well produces. Use the well pump to keep the tank full, and you can use a lower cost turbine pump and an accumulator to provide the service pressure. Just 15' of head pressure makes a big difference. The closer to the house the better.
 
Here is the setup.
Main problem is flow and pressure when grass is on (or when any two or three things are on). Usually its a 10min period when I want a shower. I have crammed the grass into as much non-awake time as possible already.
I am trying to avoid having to install a storage tank (looks ugly, collects algae, exterior pipes freeze) so I will keep that as a last option.
I was thinking booster pump and pressure tank at the house.
Main concern is, will the booster pump cavitate due to inadequate supply?
Thanks
 

Attachments

  • Well.jpg
    Well.jpg
    177.9 KB · Views: 32
Here is the setup.
Main problem is flow and pressure when grass is on (or when any two or three things are on). Usually its a 10min period when I want a shower. I have crammed the grass into as much non-awake time as possible already.
I am trying to avoid having to install a storage tank (looks ugly, collects algae, exterior pipes freeze) so I will keep that as a last option.
I was thinking booster pump and pressure tank at the house.
Main concern is, will the booster pump cavitate due to inadequate supply?
Thanks

You'll need at least 2" from the well pump to the house and you can t off for the grass before the accumulator tank rather than after. Put the accumulator tank at the house with a booster pump right before it and then manifold the household pipes out behind it.
 
You'll need at least 2" from the well pump to the house and you can t off for the grass before the accumulator tank rather than after. Put the accumulator tank at the house with a booster pump right before it and then manifold the household pipes out behind it.

I assume the boost pump will have a check valve in the line, but if it doesn't, install a check valve before the accumulator to prevent its pressure from escaping back to the grass.

-Skip
 
I had similar problem with a similar setup as my well supplies the house, the barns, the pastures and the guest house. Try adding an additional pressure tank somewhere near the furthest point from the well. The larger the better. Try that before you add the pump. It may not be necessary. I assume you have a submerged pump. What's the HP?
 
Any thought of a separate water source for the lawn. Lake, pond or separate shallow well?
 
Anyone here a genius at household water works? I want to chat about my well, pressures and flows, fixing a long standing issue with a low performing system. None of the experts can agree.

I can take a look later today and do some quick calculations. On first glance, a couple of other questions:

Couldn’t find a spec for a Goulds pump MN 186520. Is that the correct model number? We really need to know what the pump is capable of. Any idea of what it rated at? GPM verses flow/pressure. How old is it? Suspect a submersible, is that correct or is it a jet-pump?
Do you ever run out of water? You only have about 50-54 gallons in the well, even allowing for the pressure tank and recharge that’s not a lot for the duty you are asking.
The 1500’ of 1.25 inch pipe is a major line loss, at 10 GPM you are losing about 10 PSI there alone. If static water level in the well is 45 feet, there is another 20 psi loss, just to lift it out of the well.
I'm assuming this has been a continuing problem.

My initial opinion is that the pump may have a problem. Although just a guess, I suspect it is borderline on supplying all the water you need.

Gary
 
Your Achilles Heel is (are) those long pipe runs from the pressure tank to the business and house. Lots of friction in those pipes. By far the easiest solution suggested is a big accumulator tank at the house. The bigger the better. You can put several in parallel if you need to.

Your diagram shows a healthy run from the pressure tank to the point where plumbing splits off for house and business. Can't tell if that's real or just diagram. Regardless, it may be sufficient just to make sure the plumbing from the pressure tank to that split is large-diameter (ie: 2") and then arrange schedules so that the watering which has to take place during awake hours happens at the business. Assuming the well has enough flow to keep the pressure above the cut-in pressure at the tank then you'll have full pressure for the house when you need it.
 
Took a closer look at your diagram. Still missing some key pieces of info, but making some assumptions, there are two separate issues. 1.) How much water do you need; 2.) Is the well/pump system capable of delivering it.

1.) You have 5 categories for the end use.
a.) Business (assumed minimal)
b.) Grass A – 15 GPM at 30 PSI ( a good number to use for the sprinkler head to operate correctly
c.) House – assumed the main user and the driver for peak water use
d.) Guest house (assumed minimal)
e.) Grass B – used same assumption as Grass A

Since you probably want to be able to take a shower and use the sink or washing machine at the same time, a rough peak flow would be 15GPM at 40 PSI. The 40 PSI is a good number for pressure and still have all the appliances work correctly.

The major line loss is from the pump to the house; The pump needs to lift the water 37’ and transport it 1500 feet to the house. This combination of lift and length through 1.25” pipe results in a line loss of about 30PSI. As I understand it, you also want to water at Grass A while still enjoying all the creature comforts of the house. The Grass A will require 15 GPM at 30 PSI. The line loss to Grass A is small, about 3PSI, but no distance is given, I’ve assumed it to be minimal.

Since we want the house to get 15GPM at 40 PSI, and Grass A to get 15GPM at 30 PSI, the well pump must deliver at least 30GPM at 70PSI (40 psi to the house + 30 to overcome lift and line loss).

This seems about right when compared to your test. When all is off, your pressure is 48PSI. Open one faucet and Grass B, you are down to 22PSI, with everything open you get 15GPM but at basically no pressure. A faucet will work at 20+PSI but flush the toilet or take a shower and there is not enough water at a high enough pressure to have them operate correctly.

2.) A key question is whether you run out of water. The well holds about 50 gallons, the pressure tank about 80 and the piping maybe another 25; for a total of 155 gallons (about 10 minutes of use). As the water is used, the water level in the well drops (adding to the lift the pumps needs to overcome) and the well recharges. A useful test may be to turn on enough uses so that you are using 20GPM and see how long (if at all) the well runs dry. A 20 GPM residential well is pretty hefty, but this is so varied across the country, it’s hard to draw any real conclusion unless the test is done. You also need to get some specifics for the pump. From above the peak demand for well recharge is 30PGM.

I haven’t looked at pump capacity charts, but it does seem that a 2HP pump is a bit undersized to deliver that much water at the pressure you need.

Adding a booster pump would help the pressure, but if the well/pump can’t deliver the water, it does no good. Same for another pressure tank/booster pump combination although it will allow you to use a set volume of water for a somewhat longer time.

Not sure what “experts” looked at the system, but most well drillers are pretty good at figuring this out. I’ll bet the problem is in the well, either the pump is undersized or worn or the recharge rate is too low. You could change out the 1.25 inch line (that is small considering the length), that will lower the pressure required to deliver the water, but if the well/pump can’t deliver it, you are back where you started.

PM me if you have any other questions.
 
Henning - I like the idea of a tank/pump after the grass...even a 40 gal tank would never run dry from shower/laundry uses. Might be the simplest sol'n. It will be acceptable to starve the grass a little occasionally.
Skip - you're right, will need a CV
Chip - hmm a tank only, no pump. hmm... ps its a 2hp submersible pump.
Ray - I could cough up 12K to drill a new well...and that may be in the cards sometime down the road, but no surface water here :(
Gary - ref the Goulds pump. I bet that "65" was actually a "GS" Goulds std cap pump
http://www.goulds.com/GP-Product-ID-82.asp
it is 7yrs old and we pulled it this summer for a leak in the pipe but there is nothing wrong with it. This is not a change we are noticing, this pump has always done well (60psi and lots of flow at the business) - the poor perf at the house has been a problem since the beginning. Just getting around to working on it now.
-we have never, ever run out of water, or run the well dry.
Joe B - hmm Chip says 'tank only', too.....I guess I need a tutorial on what a tank does other than store water - maybe told in terms of psi and gpm, as demand is applied. I'd guess the pressurized air bubble will help maintain flow and pressure as water is used? So this may only help if the grass is not downstream of the tank, as H suggests (because the grass will draw too much)?
 
1.) You have 5 categories for the end use.[/FONT]
a.) Business (assumed minimal)
b.) Grass A – 15 GPM at 30 PSI ( a good number to use for the sprinkler head to operate correctly
c.) House – assumed the main user and the driver for peak water use
d.) Guest house (assumed minimal)
e.) Grass B – used same assumption as Grass A

House usually has two people ie shower/dishes/laundry at one time would be max use. Guest house has full bath w small shower and kitchenette sink.

2.) A key question is whether you run out of water. T

We don't and never have but the question in my mind is, will we, with changes that I decide on. I guess if we do, I am stuck with building a water tower. The grass goes for about 2hrs at 15gpm is that 1800gals in the 2hrs?


A useful test may be to turn on enough uses so that you are using 20GPM and see how long (if at all) the well runs dry.
Can you tell me if this poses a risk to any component in the system? Those pumps are expensive. Do they have thermal protection or low flow sensors?

thanks!
 
Can you tell me if this poses a risk to any component in the system? Those pumps are expensive. Do they have thermal protection or low flow sensors?
Thermal protection? No. They are water cooled (except when they run dry). This can overheat and burn out a pump motor.

Low flow sensor? Usually it is a low pressure sensor, and it is usually incorporated in the electric switch mounted on the pressure tank. This is the switch that turns the pump on at 40 and off at 60 lbs (your numbers may vary). If the pump has a little lever by it, with instructions to hold the lever up until the pressure gets up to x psi you have a low pressure shutoff kind of switch. Not all switches have that. Ask me how I know....

If you are paying attention to the test you can run the pump dry and then manually shut the pump off. A few seconds of dry running won't hurt anything because the lines won't be completely dry. But don't start the test and then go for a bike ride.

-Skip
 
Can you tell me if this poses a risk to any component in the system? Those pumps are expensive. Do they have thermal protection or low flow sensors?

thanks!

From the reference, it appears that the Goulds GS Series are NOT thermally protected. However, running the pump dry for a short period (less than a minute) will not hurt the pump. All you are looking for is the time to run dry (when you see a noticable drop in flow/pressure) at a set GPM. It's pretty rare for a home system to have a low flow sensor, not that they don't exist.

You gave some good info, I'll look up the curves for the GS series pump, and see what they say.

Gary
 
We don't and never have but the question in my mind is, will we, with changes that I decide on. I guess if we do, I am stuck with building a water tower. The grass goes for about 2hrs at 15gpm is that 1800gals in the 2hrs?

Dave:

Not convenced that a water tower is necessary, but some modifications are in order. The long run of 1.25 inch pipe and the pressure tank size/settings are the big problem. Maybe a timer for the grass so it goes on at 1AM?

See the attached description.

Gary
 

Attachments

  • Dave.doc
    23.5 KB · Views: 12
Dave, lots of talent here, but they're overcomplicating it.

Just move the house and guest house closer to the well. :)

(Of course, I'm just kidding... I never ceased to be amazed at the talent pool--and generosity with that knowledge--of the folks on this board).
 
Others smarter than me are commenting.

This is a more complicated problem than I imaginged when you first asked.
 
I never ceased to be amazed at the talent pool--and generosity with that knowledge--

Same here, Troy - I have been helped innumerable times with many many things often non-aviation. My thanks to all who have answered my calls for assistance on all topics here on POA.

Gary you have gone beyond the call here, I owe you not a beer, more like a 5 course dinner. Thanks - I am reviewing your synopsis.
 
Gary
ref the water tower.. I may get one in future anyway. When the power fails or the pump goes out, it would be nice to be self sufficient in that manner anyway. Later on that project, I hope.
ref the grass - I have them all set to not sprinkle during the heat of the day (avoiding evap. losses) and when the business is operational (too many complaints). So they start at 5pm, alternate all night til 8am. If I move them out of the 6am-8am and 5pm-11pm I am not sure we can get it all watered.
ref the water line (its fasline not pvc if that makes a diff). I would really prefer not to trench that again. A fairly difficult process. And Im not convinced it would help as the pipe from the pump up the well, into the pressure tank, back through the concrete is all 1&1/4" which cannot be changed so will a bigger line really help?
ref your conclusion larger tank and higher pressure settings.....
I suppose I could test the theory by cranking the pressure up first and seeing how it goes without a bigger tank, for a day would not hurt the pump with excess cycling. But would the higher pressure take its toll on the pump and reduce its tbo?
 
Gary
ref the water tower.. I may get one in future anyway. When the power fails or the pump goes out, it would be nice to be self sufficient in that manner anyway. Later on that project, I hope.
ref the grass - I have them all set to not sprinkle during the heat of the day (avoiding evap. losses) and when the business is operational (too many complaints). So they start at 5pm, alternate all night til 8am. If I move them out of the 6am-8am and 5pm-11pm I am not sure we can get it all watered.
ref the water line (its fasline not pvc if that makes a diff). I would really prefer not to trench that again. A fairly difficult process. And Im not convinced it would help as the pipe from the pump up the well, into the pressure tank, back through the concrete is all 1&1/4" which cannot be changed so will a bigger line really help?
ref your conclusion larger tank and higher pressure settings.....
I suppose I could test the theory by cranking the pressure up first and seeing how it goes without a bigger tank, for a day would not hurt the pump with excess cycling. But would the higher pressure take its toll on the pump and reduce its tbo?

Dave:

Didn't think that you wanted to rip up all the old line and put in a bigger one, but it would help a lot. You could try upping the pressure in the existing tank and see what happens, the pump has got enough oomph to handle it (it will make TBO!), Running a 100 psi house system is on the high side, but with the 1500 feet of 1.25" pipe you don't have too many options. I tried to think of ways to put a booster pump for just the house, that sort of works, and it would help, but then you are limited by flow, the main pump just can't supply the GPM you need for the house unless you take short showers don't run the dishwasher and washing machine! :D.

The pressure drop (line loss) for the fastline is pretty much the same as PVC. Yes, changing out the main 1500 foot line would help a lot, even though the remainder is 1.25, line loss is additive based on total line length.

Gary
 
Roger; & thanks. Will advise results of any changes.

Not a problem! It was actually kinda fun to dig out all the charts and do some of the scenaro's. You've got a tough nut to crack, that long line is a real killer, trying to force a lot of water through a small straw.

Gary
 
Yeah I mentioned them on post 7 Scott....they talk lots about raising pressure.....but not a word about flow. I suspect they get around the issue by having the system shut off if it is starving for water.
If I can't get it the water it needs, it can't make any pressure!
 
Yeah I mentioned them on post 7....they talk lots about raising pressure.....but not a word about flow. I suspect they get around the issue by having the system shut off if it is starving for water.
If I can't get it the water it needs, it can't make any pressure!

EXACTLY! They work great if you have a municipal system (or you are feeding off a large tank) that has lots of water but at low pressure. You have a problem with both flow AND pressure.


Gary
 
Doesn't really matter where the extra tank(s) are located, because pressure and reserve capacity will be added to the entire system. It's not a serial type of arrangement. I just put mine furthest from the well because that's where I could hide it.

I got my tank (40 gal) from a building materials recycling place. Brand new and cost me $25.

Another thought might be to change to a sprinkler system with lower volume and pressure requirements. I built a watering system for our indoor arena (70'x120') to keep the footing moist in winter. I used low pressure heads and 1/2" pvc, and I can water the entire thing at once and the system hardly knows it's there, and don't need to run it for more than 30 mins.

As to adjusting your pressure switch, I would be cautious about going anything north of 80 lbs, especially if you have older copper or PVC. I had mine set at 80 for while, but dialed back to 60 as my house is 30 years old and has the original copper.

I guess it's the pilot in me :)
 
Back
Top