Pumping through long run of pvc?

[Bigfellor]

Hello all. Last year was our first with an AGP. I'm looking to make some changes this year and part of that is to relocate the pump and filter to an out of the way area

I'm considering putting them in the corner of the yard where I'll be able to plug into gfci outlets. With the equipment there i was planning on running PVC underground along the fence line on the side yard and along the back to the pool. Roughly 85' or so. Will I run into any issues with this? I don't have the model number at the moment but the pump is the intex pump with sand filter. 0.5hp maybe?

Thanks

 

[Mdragger88]

That seems like a long way for a little intex pump - i have seen people go 20 ft or so away but with a bigger set up than u likely have. I would definitely try a practice run first before sweating & digging.

 

[Teald024]

Relocating is definitely doable, but I’d upgrade to a 1 hp (non-Intex type) pump. Variable speed or 2speed.
As spring comes along you will likely find a bunch of used ones on the selling sites. A word of caution though, with the deep freeze you all had, be sure the pump isn’t cracked.

 

[Darin]

It sure appears like it will work for you. I just did a google search for flow rate calculator. Now lets assume that the number of elbows will be the same. Also motor/pump size does not matter since you are utilizing the same equipment and this is based on flow with a constant pressure of 10 psi.

Using 1.00 inch pipe at 10 psi and 22 foot of run = 50 gallon
Using 1.00 inch pipe at 10 psi and 100 foot of run = 24 gpm.

You could do bucket test and time how long it takes you to fill a 5 gallon bucket to SWAG where you are and where you will be with the addition length.

I would not buy anything new until you know that it wont work. Seems like motors/pumps are always way oversized for what is needed. Also don't overlook the possible need to increase conductor size if going to a larger motor.

 

[JamesW]

Use all 2" pipe and it will be fine.

 

[Bigfellor]

Edit: See below. I did the quote wrong.

 

[Bigfellor]

It sure appears like it will work for you. I just did a google search for flow rate calculator. Now lets assume that the number of elbows will be the same. Also motor/pump size does not matter since you are utilizing the same equipment and this is based on flow with a constant pressure of 10 psi.

Using 1.00 inch pipe at 10 psi and 22 foot of run = 50 gallon
Using 1.00 inch pipe at 10 psi and 100 foot of run = 24 gpm.

You could do bucket test and time how long it takes you to fill a 5 gallon bucket to SWAG where you are and where you will be with the addition length.

I would not buy anything new until you know that it wont work. Seems like motors/pumps are always way oversized for what is needed. Also don't overlook the possible need to increase conductor size if going to a larger motor.

Talk to me like I'm an idiot ...

Why a 10 psi constant pressure? Is that standard for the returns on these pools? Also, I'll be needing to lift the water a couple feet. The pool will be sunk 3 feet into the ground with the Hayward skimmer attached. Once piped I think the output from the skimmer will be a couple of feet below ground and need to come up to the pump. Also I'm using (or planning to use) 1.5" PVC. @JamesW mentioned 2"; why? Wouldn't that decrease the flow rate and require a more powerful pump?

 

[JamesW]

Also, I'll be needing to lift the water a couple feet. The pool will be sunk 3 feet into the ground with the Hayward skimmer attached. Once piped I think the output from the skimmer will be a couple of feet below ground and need to come up to the pump.

It’s the height of the pump inlet above the water surface level that matters; not how far down the suction is.

The pool could be 100 feet deep and if you were pulling from 100 feet down from the main drain, it would not make any difference from pulling from 50 feet deep or 10 feet deep or 1 foot deep.

The only thing that matters is the height of the pump inlet above the surface of the water.

Make sure to get a self priming pump.

Also I'm using (or planning to use) 1.5" PVC. @JamesW mentioned 2"; why? Wouldn't that decrease the flow rate and require a more powerful pump?

The size of the pipe reduces the restriction. So, bigger is better.

For example, if you wanted a flow rate of 40 gpm through 100 feet of pipe and you used 1.5” pipe, the velocity would be 6.31 ft/sec. and the head loss would be 10.2 feet.

If the pipe was 2” PVC, the velocity would be 3.83 ft/sec and the head loss would be 3.0 feet.

The distance is irrelevant as long as you use the correct size pipe.

For example, at 40 gpm, if the system was 1,000 feet away, you could use 3.3” diameter pipe to get the same resistance as 2” pipe at 100 feet.

If the system was 10,000 feet away, you could use 5.3” diameter pipe to get the same resistance as 2” pipe at 100 feet.

If the system was 100,000 feet (18.9 miles) away, you could use 8.5” diameter pipe to get the same resistance as 2” pipe at 100 feet.

There would be 294,779 gallons in a 8.5" PVC pipe at 100,000 feet long.

You could put the pump and filter in China if you wanted and it would be fine as long as the pipe was the correct size.

You could pump all the way around the earth if you used 36" diameter pipe.

There would be 6.7 billion gallons just in the pipe.

It would take 116,336 days (319 years) for the water to go through the system.

The water velocity would be 0.0037 ft/sec.

volume of pipe length 100000 feet diameter = 8.5 inches - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

Hazen-Williams Friction Loss Equation - calculating Head Loss in Water Pipes

Friction head loss (<i>ft_H2O per 100 ft pipe</i>) in water pipes can be estimated with the empirical Hazen-Williams equation.

www.engineeringtoolbox.com

 

[JamesW]

Also I'm using (or planning to use) 1.5" PVC. @JamesW mentioned 2"; why? Wouldn't that decrease the flow rate and require a more powerful pump?

If smaller pipe was better, you would use the smallest pipe you could get.

You would use 3/4" or 1/2" or maybe even 1/4" pipe.

Bigger is definitely better up to a point.

You should not need more than about 40 gpm for any reason.

I am assuming that the flow will not be more than 40 gpm.

If you know what the flow rate will be, we can give better advice.

 

[Teald024]

Talk to me like I'm an idiot ...

Why a 10 psi constant pressure? Is that standard for the returns on these pools? Also, I'll be needing to lift the water a couple feet. The pool will be sunk 3 feet into the ground with the Hayward skimmer attached. Once piped I think the output from the skimmer will be a couple of feet below ground and need to come up to the pump. Also I'm using (or planning to use) 1.5" PVC. @JamesW mentioned 2"; why? Wouldn't that decrease the flow rate and require a more powerful pump?

10psi was just an example he used. There is no fixed pressure drop.
If you have the pump inlet above the level of the pool surface, then you can’t use the Intex pump. Intex pumps aren’t self priming. You would need a self priming pump (one made for an inground pool).
The larger pipe size decreases the pressure drop. Flow rate is gallons per minute. In a larger pipe, the velocity would be less, but the flow is the same. The lower velocity has a lower pressure drop. The lower pressure drop allows the pump to pull less power.

 

[Bigfellor]

If smaller pipe was better, you would use the smallest pipe you could get.

You would use 3/4" or 1/2" or maybe even 1/4" pipe.

Bigger is definitely better up to a point.

You should not need more than about 40 gpm for any reason.

I am assuming that the flow will not be more than 40 gpm.

If you know what the flow rate will be, we can give better advice.

How do I determine what the flow rate will be? By the pump rating?

The outlet from the skimmer is 1-1/2" (I believe) and the input to the Intex filter/SWG is also 1-1/2". If I use 2" to deliver the water to the pump will there be any issue stepping down to 1-1/2" at the filter?

Thanks for all the info so far.

 

[JamesW]

How do I determine what the flow rate will be? By the pump rating?

You would look at the pump performance curve or the performance chart to see what the performance is for different systems.

Use all 2" as much as possible and then reduce down to 1.5" as needed.

 

[Teald024]

Intex uses proprietary sizes for their connections. They don’t match standard pipe fitting sizes.
If it is a Hayward skimmer, then it is 1-1/2 NPT fitting.
I doubt you will find a pump curve for the Intex pump. Most of the Intex ratings are given at zero head.

 

[Bigfellor]

Intex uses proprietary sizes for their connections. They don’t match standard pipe fitting sizes.
If it is a Hayward skimmer, then it is 1-1/2 NPT fitting.
I doubt you will find a pump curve for the Intex pump. Most of the Intex ratings are given at zero head.

Yea I learned all about the Intex fittings last year when I converted my Summer Waves pool to work with the Intex filter and SWG. I managed to get some adapters made without too much difficulty.

 

[Teald024]

Got some made?

 

[Bigfellor]

Got some made?

Not my video but basically this is what I did. Works great.

 

[Bigfellor]

So...if my intex pump inlet is below the water level of the pool it should work right? Does the length of the run matter then? Just eye balling but where I want to put the pump is lower than where the water level will be. I need to measure though.

 

[JamesW]

So...if my intex pump inlet is below the water level of the pool it should work right?

Right.

Does the length of the run matter then?

The length always matters. Without knowing the performance curve of the pump, I would recommend 2" PVC.