ANOTHER Pump question (with sketches!)

[CrimsnTide]

I am looking for some accurate information on pump sizing. Just built a pool and I have two issues.

1)Nobody can ACCURATELY tell me what is the most efficient size pump for my pool right now

2)Nobody can tell me what would be the BEST choice for a pump when I add solar heating. I am THINKING a Variable Speed OR TWO-SPEED pump just off the top of my head.

In addition to the two sketches below, I will try and accurately describe what I have and what I hope to accomplish. Having never owned a pool, I’m sure I’m going to miss something important, so please be patient. We had a retaining wall built on part of a hill to give us more room for a pool. This area is ROUHLY 38’ x 80’. The retaining wall itself is ABOUT 80” tall and sit’s on roughly a 3:1 slope. Our equipment/pad sits OUTSIDE the retaining wall area and is BELOW the pools water line. The solar panels will also sit outside the pool area and will be BELOW the pools water-line. The retaining wall was built a while ago and the pool was finished and filled 6 weeks ago. Located in So. Cal (Anaheim). I would say the pool gets the sun from 7:00 A.M. until about 5-6:00 PM when the neighbor’s tree starts to cast a shadow. The proposed area for the solar panels would get the same amount of sun.

Pool
15 x 50 Rectangular Shape (Shelf area not calculated)
4’ to 8’ deep – (Shelf area not calculated) - (symmetrical for the most part)
No Jacuzzi/fountain/features
TWO Skimmers – Each Skimmer connected to two drains in pool. Pipes to pump are 2 ½”.
Only 4 returns back to pool (print/drawing reads 6. Maybe 1” for each return?) Talking to PB now
Deep Heating/Floor heating 3 outlets on pool bottom – I’m going to SAY 2 ½” pipe. Size unsure
1 dedicated line for Vacuum – I THINK its 1 ½”

Equipment – All Jandy (Current)
Heater = LXi
Pump/Mtr. = Stealth/.75hp
Filter = CL580
SWCG = JANDY PLC1400

Description (measurements)

From the Skimmer on the END, (closest to pump) I would say it’s a distance of 25’ feet to the pump and is 2 ½” pipe. The Two drains below the skimmer would add another 9-10 feet of pipe.

From the Skimmer on the SIDE, I would say it’s about 44 feet to the pump. The drains in the deep end add about another 20-22 feet of to the CENTER POINT (TEE) for the two drains and another 4 feet on each side of that for EACH drain. The distance for ONE DRAIN (deep end) to the pump is APPROX 69 feet. PUMP>DRAIN (44’)>TEE(21’)>DRAIN(4’)
There are two drains going of TEE – See pic.
The Vacuum has about 48’-50’ of pipe (1 ½”?) from the pool to the pump.

As mentioned, we have 4 returns. Size unknown but I think from our pictures it’s 1” to 1 ½” pipe – probably 1”

From the pump it would be 44’ to the first return, another 34’ to the second return, and then another 14’ to the third return (The end return being 94’ from pump. All three of these returns would be on the same line.
The other side of pool has the 4th return and it’s roughly 43’ to the pump. I’ll have to check the pics, but it probably “T’s” at the end of the pool. One side of the TEE feeding the three returns, the other side feeding only one return.

The difficulty I have is what effect my pump has (or doesn’t have) with it being BELOW the water line. If you can view the second pic I have attached, it’s the on the OUTSIDE of the pool area looking at the equipment pad. (First pic is an OVERHEAD view) Also, although not unusual, my solar panels WILL be BELOW my pump (equipment pad). I have no choice but to ask the experts here for advice. It’s my fault the solar panels are an afterthought. I have the room. I will have the panels (only) installed probably this week with pipes going to the equipment area.

My question is this: What would be the most logical/economical pump. I have the opportunity to do this the right way, right now. I don’t want adequate, I want efficiency – even at a little extra cost. My goal is to EXTEND our swim season and keep the pool at a comfortable temp starting in April and hoping to get into October…. I going to say my electric is ABOUT .15 cents per KWh.
Sketches

Is my pump efficient /strong enough?
Two-Speed pump?
Variable speed pump?

Anyone care to take a crak at this?

 

[mas985]

Pump efficiency is directly related to flow rate. The higher the flow rates, the more energy is used to generate that flow rate and the less efficient the setup. So in general, smaller pumps are more efficient than larger pumps. Two speed pump are more efficient than single speed and a VS is slightly more efficient than a two speed.

So the simple answer to your questions:

1) The smallest pump available will be the most efficient. This includes VS pumps because the speed can be adjusted. However, if you are looking for the most efficient VS pump, then I would have to say that is the MaxFlo VS. But they are all pretty close.

2) Because solar is below the water line, any pump would do. But even on a two story roof, nearly any pump will work for solar. There are only a handful of AG pumps that wouldn't work so well.


But I have a few more questions:

1) Did you already purchase the Stealth and is it a two speed? - You could just swap out the motor for a two speed.

2) Why do you want efficiency. Save money or polar bears?

Often times the cost savings of a VS pump will barely exceed that of a two speed pump. The more you pay in electricity, the more cost effective a VS can be. However, they do have draw backs and the biggest is that the drives can and do fail, albeit not very often, but to replace them is quite expensive.

The nice thing about a VS pump is that it is variable and there is no need to "size" a pump. However, in this case, there would be no need to "size" a pump either because there is nothing in your pool setup that would require a large pump so the smallest available pump would do. And since the pool is below water level, an AG pump would also do.

So choosing a pump for a pool without a spa is actually pretty easy. Just choose a small 2 speed or VS speed pump. The choice between the two speed and a VS is a little more difficult. If money is not an issue, then I would say go for the VS. But at $0.15/kwh, either way is a good choice economically. But I think that is a bit low for CA.

 

[karmabiker]

... Mark nailed it.

Would love to see pictures!

 

[CrimsnTide]

Mark,

I appreciate the quick reply.

I am kind of quirky in the since that when I mean "efficient, it does not always have to do with the bottom dollar. Efficient to me is what works the FIRST TIME and will last. I'm not the one to save a buck and have to do it twice as often. I'll even spend a little more to NOT spend the time having to do it twice as much...

Our pool is right at two months old and I still have a problem of getting numbers from Jandy or my pool builder on my pump rate/flow. I would have thought they would have these calculations and be able to check their math or at least give me the numbers to help me figure it out. I'm afraid is all that I'm getting is "tribunal knowledge" with them (PB) saying this pump is adequate for your pool size. Which I'm sure it is because we did NOT have any additional features installed. (I didn't even want a heater). So with that I relied on information gathered from other sites. Although it may NOT be accurate, it is compared across the board. I'll shorten down my spread sheet and show you this part:



I will CONCEDE, I used the Pentair page to calculate the Run Time in hours. This MIGHT be a little off, however, the same information was used in getting the other pumps costs. Amps I got from the manufacturer sheet for that size pump. The only real "unknown is calculating RUN TIME for our pool. Definition of RUN TIME is how long it takes to CYCLE the whole volume of the entire pool. Having going to Pentair's website and for their 3/4 HP motor, they are saying it takes 11.2 hours. However, by using a 1 1/2 HP, I can do it in just UNDER 7 hours... I have been speaking with my PB to get the numbers THEY calculated for the "dynamic head" but cannot get it.

My issues started before wanting to install solar. I didn't think the pump (motor) was large enough because I felt the skimmers were not working to their full potential. I now find out from the wife that one of the skimmers has to be turned OFF and the other "adjusted" to get our vacuum to work. doesn't seem right, but if that's what I need to do - I guess I will. I'm just afraid of any EXTRA need from our solar install. I have even read Techo Solis only recommends 12 panels max. (I was thinking 13).

Quote from mas 985:

But I have a few more questions:

1) Did you already purchase the Stealth and is it a two speed? - You could just swap out the motor for a two speed.
The PB has been GREAT. With my concerns about the motor, they are willing to come out and SWAP the motors. I asked about the VS, but they said they would have to change "everything". I have read they can swap me the two speed motor with little/no problems.

2) Why do you want efficiency. Save money or polar bears?
I would like the best pump for my situation and not be told "it's adaquate". If they're going to tell me this, I'd like them to prove it with something other than "it's what we use ALL the time.

I have "conceded" on the VS pump. The costs for MY set-up will NOT be worth it. However, I do feel a TWO_SPEED could be justified - but again, I would like some kind of verification it would be justified. I do have a choice and they are wanting to know what "I" want to do.

I quoted .15 cents per KWh, but it's actually about .16 cents. I live in Anaheim. (Yes - Where the "RAT" lives)... We are "off" Edisons grid and I pay only to Anaheim. Not sure why, but it's been this way for the time I have lived here. Anaheim charges me a base rate or what is called a "Basic Lifeline" - a bare minimum. 540 KWh @$58.75. Also these at a "reduced rate" Add'l lifeline water 250 KWh @ $27.20, Add'l Lifeline heat 550 KWh @ $59.84. My usage ABOVE these were 1093 KWh @ $176.08. With these "good" rates, residents do pay a "RATE STABILIZATION" of $52.90. And of course taxes, sub taxes, pre tax, and what any other tax they can think of... Anaheim is actually pretty fair from what I have heard...

Karmabiker - although it's not elaborate or anything real special, I will try and take some pics. My wife and I LOVE our new addition. My wife has had a pool before and has always wanted this. The boys are older now (17 and 14) and people keep saying "Why did you get a pool now, the kids are older and they won't use it".
My wifes response is "We didn't have it built it for THEM. It's what I wanted and they can use it anytime they want!"

Although it doesn't have the bells and whistles others do, we are extremely happy with it and its "uniqueness". We were definitely on a budget and had to choose between "bells and whistles" or size. She chose size. Please - no jokes. Apparently size does matter, so she went with a large pool instead.

 

[mas985]

Efficient to me is what works the FIRST TIME and will last.

Most any pump will do that so you need to be more specific. What makes you think any pump won't "work" with your setup? There isn't a lot of difference in reliability except for some of the issues with VS pump but those are fairly rare.

Our pool is right at two months old and I still have a problem of getting numbers from Jandy or my pool builder on my pump rate/flow.

That's because it is not very straight forward to do that. To get accurate numbers the plumbing has to be fully characterized and the operating point calculated from the pump's head curve and plumbing curve intersection. But in the end, flow rate is not all that important. Most pools need about 3-4 hours of run time (read study in my sig) and flow rate doesn't change that very much.

However, I do feel a TWO_SPEED could be justified - but again, I would like some kind of verification it would be justified.

What would be justification in your mind? Two similar sized pumps are going to have the same performance so who makes it doesn't really make a difference. The only thing that matters is pumps size. Since you do not have a spa or water feature and do not have high flow rate requirement the smallest pump will do. I have a 1/2 HP pump on my 20k pool so I practice what I preach. I also, only run my pump 4 hours per day (3 of which is on low speed). So again, the smallest pump will be fine.



But I think your best option is to just replace the motor on your current pump with a two speed. You will save energy and money and it will work fine. I know that is not what you want to here but I could go through mountains of pump data with you and show you that it really doesn't matter much which two speed pump you get. What is important is that you get a two speed pump and you run it on low speed most of the time.

 

[karmabiker]

The quick and dirty of it is that your pool will need somewhere in the 4-6 hour runtime range on LOW.

The turnover calculations don't apply in residential pools.

Best option, get a 2 speed and run it on low most of the time. Lower electric bills, less noise, more efficient filtration, less wear and tear on the pump ( wet end ), need I go on?

 

[sash501]

I must say that I've been lurking on this site for nearly a month now and this thread has finally started teaching me (noob) some valuable information.

I'm in South Florida, where we use our pools year round and I will be posting soon for recommendations on a new filter and possibly new pump. I'm so impressed with this thread's response and hope I have someone like mas985 to help me out.