What size pipe to plumb my pool and spa?

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repairman

repairman

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Nov 2, 2016
203
Lompoc, CA (central coast)
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I'm replumbing my 22k, 60's era IG pool. I'm moving my spa to the shallow end of the pool and combining systems so they share the same VS pump, Hayward 4800 DE filter, and Pentair MiniMax NT gas heater. The spa will overflow into pool and I will use valves to select how much water goes to the pool and/or spa. I want to be prepared for solar and a rock waterfall on the right side of the deep end, although that's not on the drawing. I've read Mark's posts on hydraulics but still don't know what size pipes I need.

For the returns, I thought 2 1/2" or 3" up to the Y and 2" up to the 1 1/2" going through the wall, but should I use bigger up to the 1 1/2"? I plan on circulating water on slow speed maybe 24/7. From the Pump Room to the last return on the left return branch is about 75' and 65' on the right. I have 7 returns which many say is excessive but I can use 1/2" eyeballs and keep water pressure
I have one cement box skimmer I'm keeping, so the suction will be through the skimmer and the equalizer inlet, two 1 1/2" copper pipes into one approx. foot long piece after which it joins larger PVC to the pump. What size should the suction pipe from the skimmer be? Skimmer to pump is about 53 ft. .


It's about 33' to the spa. I've read I should use 3" to the spa. The spa has 4 jets. Before, the two jets farthest from the Ts didn't have enough pressure. That's why I drew the spa return with a Y going into 2 branches that each Y again and feed two eyeballs. Is this necessary to keep strong pressure through all inlets if I use bigger than the old 1 1/2" pipe. How far should I use the 3" pipe, to the first Y or the second Ys, ...?
and what about the line from the spa skimmer/MD to the pump?
Finally, if I want a waterfall on the right side of the deep end, do I need and extra pump or can a good vs pump handle it. Could I just connect to the end of the left return branch, even though it has 4 returns (1/2" eyes so equivalent of 2 normal returns). Or would it be better coming off the right return line in the diagram, (3 returns, small eyes,) and again, what size pipe? I would valve it to adjust or turn off/on that line. If I don"t use it as a waterfall, maybe a slide.
I hope you can see the photo of my diagram.
Thanks,
Repairman
 
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Re: What size pipe to plumb my pool and spa?

My two cents is to use loops on both the pool and the spa and 2" is fine for the pool. Yes on 2.5" or 3" to get to the split for the spa.

I would add a skimmer so you have flexibility depending on breezes. I wish I had a 2nd skimmer on mine which is much smaller. The leaves are not going in the same direction as the prevailing wind cause of the way the breezes swirl around the house and fences.

I would have a separate line for the waterfall.

I would definitely add a waste line, and seriously consider an auto-fill as well.

As far as what size you need, bigger is always better, but 2" is already a pretty good size. It's not that many years ago that many PBs would have rammed it all through 1.5" (other than the spa).

There's better experts here than me and I'm sure they'll chip in as well.
 
Re: What size pipe to plumb my pool and spa?

Thanks, Needsajet,
I was planning on having the spa and pool on different loops. Wouldn't I want to run as big a pipe as possible out of my pump, filter, and heater, and before it hits the valve to the pool or spa? Is 3" there that unusual these days since it's 3" to the spa?

I bought a bunch of 2" pipe and fittings for the pool return lines but maybe I'll take take them back and get 2 1/2". Yes? No? Will it make that much of a difference if I'm running on low speed?

I've done everything myself, breaking out all the deck, core drilling, etc., but I thought breaking though the wall and making a skimmer box would be a job I didn't want to do. Unless there's an easier way I'll go with my one skimmer.

Separate waterfall line - starting from where and how big? Figure about a 4' high waterfall, if I do it.

Where do you tie the waste line into, the house main drain? Back in 97 I tied into and replaced some of it, and I wasn't looking forward to digging down there again, but I guess it's not that much trouble. Right now I backwash into the alley, although backwashing isn't that effective so I tear the filter apart and spray the panels (in the alley). Currently, when emptying, I don't put chlorine in for awhile and pump out into the yard to water plants. I read it was safe to do that.
 
Re: What size pipe to plumb my pool and spa?

Yes, definitely spa and pool on separate plumbing circuits. My words were confusing!

What I meant by a loop is, for example... at the upper right in your drawing, you show the two return lines ending at the last return. By a loop, I mean to continue and plumb the two branches back together, given that they look close and easy to do. This will even up the pressure, particularly on the last two returns. If it was a long distance, or there was something in the way (like rock), I wouldn't bother to do this.

On low speed, 2" is more than enough. Occasionally you'll run on higher speed for skimming (lots of bugs, pollen or leaves) but the added electricity cost for those temporary situations will be occasional. And most of the footage is split between two branches anyway, which is very similar to one run of 3".

Waterfall line starting from the pad so you can control it. Size depends on the design flow for the waterfall, but just guessing what you have in mind, and if it was me, I'd do it in 2" as well.

As far as waste, sorry sorry, I didn't even look to notice that you're in California so you don't have rain to get rid of. Skip it. Down here, the waste line drains into the sewer after an air gap.

If you're real keen on 2.5", go for it. It won't hurt anything, that's for sure. Spas are done on bigger pipe because you want tons of flow coming out of the jets.
 
Re: What size pipe to plumb my pool and spa?

Loops are to compensate for the head loss between returns but that can also be minimized using larger pipe. Plus loops around pools don't do much at all if anything because the run lengths tend to be long, it negates any benefits. Around spas they can help but then if you are using large pipe between the jets, again, it shouldn't be an issue.


I have one cement box skimmer I'm keeping, so the suction will be through the skimmer and the equalizer inlet, two 1 1/2" copper pipes into one approx. foot long piece after which it joins larger PVC to the pump.
Click to expand...
If your two suction side pipes are only 1 1/2" you don't want to unbalance the system with pipes that are two big on the return side. This could lead to cavitation in the pump. So given this, you don't want more than two 1 1/2" return lines or a single 2" return line.

On the spa side, everything depends on the type of jet you are using and the flow rate requirement per jet. But what you want to do there is to do a split in the middle of the spa so both pipes to the jets are the same lengths. You don't need the second TEE if you use 2.5" pipe around the spa.

Look at the picture below. Notice how the air (upper) and water (lower) pipes are wrapped around the spa. In this case they used a loop where the ends of the pipe are connected.

other_builders_spa-resized-600.jpg


I think they are using a Hartford loop which is always a good idea for spa so you don't need a blower.
 
Re: What size pipe to plumb my pool and spa?

There ya go. Glad one of the gurus chimed in! :)

Sorry I musta missed that you were using 1.5" suction. I would avoid that if possible. I thought you planned 2" suction and then adapting to 1.5" because of the existing pool wall. If the latter is the case, and given the major rehab work you're doing, there's no way I personally would go to all that work just to re-plumb your return side in 1.5"
 
Re: What size pipe to plumb my pool and spa?

Thanks All,
I knew I would get the word. Needsajet, yeh, although the pool originally had just two 1 1/2' returns, I am making it better so I don't want to go 1 1/2' returns. And yes, I was planning on punning 2 1/2 or 3 for suction connecting with the short 1 1/2 lines through the wall. In my original post, I said the copper would join into a larger PVC and asked what size pipe that main suction pvc should be. Still need to know that. Looks like we're getting there.

Mark, if there are two 1 1/2" lines that join to one for only a foot before they expand out to 2" or larger pvc, is that enough resistance to cause cavitation, given that I'll be running it mostly on low? One way to get more suction volume through the wall is to use the deep end, left wall (by the skimmer, top left) return line (about one foot long) for a suction line instead, making the suction leg three short 1 1/2" suction lines flowing into bigger PVC (with the first two going through that 1 foot of 1 1/2" before it ties into the larger PVC. What do you think about that and what size PVC suction pipe should I use in that case? (I could put a 2-way valve on that return I'm talking about, so it could be used either for suction or return, but I have a feeling you wouldn't like that idea. The only way I can imagine that that would be useful is if the system was ok and had no cavitation on low without it, but you'd switch it to a suction line if you wanted to run on high.) If that extra suction line is in, what size return lines should I use to the Y and after?

Are those 2 1/2 or 3" pipes going around the spa? I want powerful jets so what do you suggest? The holes are 2 1/4' now but I can cut them bigger if necessary. The plumbing scheme for the spa you describe is like what was in there but with bigger pipes. It had 1 1/2". So, to be clear, if I use 2 1/2" pipe to the jets, the farther jet on the end of each branch of the T won't be softer? If it is would it be a big enough difference to worry about. I've got a feeling it's going to be a big improvement anyway. So, I guess I'll run 3" to the spa T, yes?

Thank you so much! I'm upping my membership because you all are so helpful!
 
Re: What size pipe to plumb my pool and spa?

Mark, if there are two 1 1/2" lines that join to one for only a foot before they expand out to 2" or larger pvc, is that enough resistance to cause cavitation, given that I'll be running it mostly on low?
Click to expand...
That isn't the issue. A short piece of pipe isn't going to make a difference. The issue is the relative head loss between the suction side and the return side. When suction head gets close to return head, you can run into problems. You made it sound like the copper is going all the way from the pool to equipment pad. Is that not the case? Your drawing is not very clear as to what is 1 1/2" copper and what is planned PVC. If the copper is just 1 foot from the pool wall and then transitioned to 2" back to the pad, then that is fine and you can do the same on the return side. Just balance the two sides as best as possible with the suction side having a bit more volume than the return side and you should be fine.


Are those 2 1/2 or 3" pipes going around the spa? I want powerful jets so what do you suggest?
Click to expand...
They can be whatever they need to be but you should really choose the jets first so then you can choose the pipe size. 4 jets is not a problem in most cases. But are you replacing the spa jets (i.e. nozzles) too or using the existing ones?
 
Re: What size pipe to plumb my pool and spa?

The copper doesn't go around the pool. It's only the foot long piece os copper pipe and the rest is pvc on the pool suction line. Would it be best to make that suction pipe 2 1/2 and the returns 2"?

I'm replacing the jets and all spa plumbing. All I had before on spa jets were eyeballs, I think 1 inch. I'll measure them. I didn't think about any other kinds of jets. I'll call Waterways and Aquastar tomorrow and ask questions. Can you make any recommendations?

I was going to use the same variable speed pump for the pool and spa with automation. When I buy my variable speed for the pool I'll have 3 extra pumps, the 1 hp Sta-Rite I currently use for the pool, a 1 hp American Products that drives the independent spa system now, and a 1 hp Hayward MaxFlo Dual Speed. Should I use one of those to run the spa jets, if so, which one, or just let the vs pump do it? If you suggest using a second pump for the spa, how should I plumb it in?
Thanks
 

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Re: What size pipe to plumb my pool and spa?

Mark,
Should I use 2" or 2 1/2" on the suction side, (since you said a little more volume on the suction side). The length of the suction side is 53' from skimmer to the pad. Return is 23' of 2 1/2" where it splits to a 50' leg and a 35' leg, both legs 2" pipe. I assume the return side has more head loss since it goes through the filter and heater and is longer, with two legs. I'm about to glue in 2 1/2 for the suction side so let me know asap.
Thanks
 
Re: What size pipe to plumb my pool and spa?

Sorry I missed your other post. It wouldn't hurt to go with 2 1/2" on the suction. It can prevent air leakage issues down the road. But on the return, I don't think 2 1/2" would buy you much but wouldn't hurt either.


Should I use one of those to run the spa jets, if so, which one, or just let the vs pump do it? If you suggest using a second pump for the spa, how should I plumb it in?
Click to expand...
Does the spa have a separate loop that is not part of the spa jets (i.e. a separate return and suction line)? If not, then you may just want to stick with a single pump. You don't have many jets anyway so the flow rate will probably not be an issue.

But the spa jet nozzles are not the eyeballs. The nozzles are deep within the spa wall and you can only access them with a long socket wrench. They look like this:
 

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Re: What size pipe to plumb my pool and spa?

If you are going with a VS pump, that might be a better choice for both the spa and pool because you can then dial in the exact strength of the jets you want. With a single speed pump, you get what you get. On the other hand, if you want to run the pool or water feature at the same time as the spa, it is better to have two pumps. Your choice!
 
Re: What size pipe to plumb my pool and spa?

I am not sure I understand your question. Do you want to go with a single pump system so that the VS can control the flow rate to the spa jets too OR do you want to go with a two pump system where you have a jet pump dedicated to the spa jets without any speed control?

A two pump system is not necessary and it would limit control of the spa jets. However, it gives you the benefit of being able to run the pool pump at the same times as the spa jets (but without heat and filter).
 
Re: What size pipe to plumb my pool and spa?

To answer your question, I don't need the pool and spa on at the same time and don't need to adjust my spa jets, just as long as they're strong. However, I would like to run the spa jets and the waterfall at the same time. If no waterfall it looks like one pump would do but what about with the waterfall? Does that require two pumps?

I'm including this diagram to see if this can work in my case, which is:

I don't have a main drain so the suction line would just be skimmer and spa joining before the pump.

I don't need the spa jets and pool working at the same time.
I don't think I need to adjust the jets as I've always just liked strong and powerful. Have you found adjusting them useful?
I want to run solar about 15' to the garage and 9 ft to the roof. I don't know anything about pool solar. I have a Pentair MiniMax gas heater now. Is it better to run the water up to the roof or use solar panels for electricity to run an electric heater? I'm in Central California. I think my city has filled it's quota on people who can sell back to the grid but I will check.
My spa will overflow sometimes into the shallow end of the pool, 35' from the pad.
I want to circulate the spa for sometime each day.
I will automate.
I'll have 2" pipe feeding a waterfall 75' from the pad, flowing into the deep end.
The waterfall should be able to run at the same time as the spa or pool.
I currently have 3 working pumps, but don't mind buying a VS pump. I already have a Sta-Rite 1 hp on the pool and an American Products 1 hp (2' in 1 1/2' out) on the spa, and a Hayward dual speed MaxFlow 1 hp (1 1/2' in and out) that came off an old spa set-up.
I'll have 3" line going to and from the spa. At the spa it splits to 2" line feeding 4 jets. The spa drain will also be 3" back to pad.
Pool suction is 2 1/2", and return is 2 1/2" to 2 branches of 2" feeding 7 returns total.

I'd rather just have one vs pump, but if I need 2 pumps, what would the second pump be dedicated to, the spa or waterfall?
Thanks.
 
Re: What size pipe to plumb my pool and spa?

Depending on the size of the waterfall, you may want to have a waterfall pump just for that anyway. Plus they are usually low head high flow pumps to get the proper effect. Will it have it's own suction line? Depending on the size, it may need that. Have you determined the size of waterfall and flow rate requirements for just that?
 
Re: What size pipe to plumb my pool and spa?

I envision a 1 ft across weir, medium flow, which I believe will take 25 gpm. It will be about 4 ft high and about 75 ft from the pump. I calculated about 16 ft of head if you include the turns and fittings. I didn't plan on it having its own return but tell me if I need one. The question is do I need two pumps. It seemed like I could get by with 1 vs pump for the pool and spa but is that still true with the waterfall and spa running? The spa will have 4 jets, Hydro Air 10-5100s, with a flow rate of 13 gpm each. So the main question is do I need two pumps to feed the spa and waterfall at the same time?
I was advised to run 3" from drain and skimmer to pump and 2" return line to spa where it T's into a full circle of 1 1/2" to feed the jets. Does that sound right? The stated reason for the 2" return, rather than 3" was to give more pressure to the jets. Also Mark, you said I would be fine with the T branching to 2 jets each. What do you thin of the full circle idea? Worth it or not in my situation? No problem either way with me.
So many questions. Thank you,
Repairman
 

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