What size pipe to plumb my pool and spa?

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

As far as flow rate is concerned, you don't need two pumps. However, the real issue is really about heating the spa and not the waterfall so if you want to have a waterfall at the same time as the spa without sending heated water into the pool, then I would get a separate waterfall pump.

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.
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If you use 2" on the return, you really don't need 3" on the suction. 2 1/2" would suffice because the 2" will be the limiting factor so you won't notice any difference with the 3" vs 2 1/2" on the suction. As for the loop, if you can do a loop, that's fine but I would not use 1 1/2" pipe. The larger the pipe around the loop, the less a loop is even needed. Personally, I would use 2 1/2" suction and return pipe for the spa and loop that size around the spa. Smaller pipe results in more disparity between the jets, loop or not. The larger pipe removes the need for a loop because there is very little head loss between the jets.
 
Re: What size pipe to plumb my pool and spa?

Hi Mark,
Thanks again. I will try to plumb the spa without a blower and see how that works. I will definitely run a 3" suction line from the spa and 2 1/2 to it. You said if I use 2 1/2 I wouldn't need to loop or use a second tee. Not sure exactly how to hook up the two jets on either side of the first tee. Below is a pic of the jet the rep at SpaDepot recommended to replace the ones I had in before to fit the 2 1/2" holes in the spa wall. For the water lines, do I run the two jets on either side of the split in series, reducing down from 2 1/2 to 1 1/2 at the first jet, expanding back out to 2 1/2 to the next jet and reducing again at the second jet, or tee off each branch at the first jet, reduce down to 1 1/2, cap the other side of the jet, then continue the 2 1/2 to the 2nd jet, the last jet on the branch, reduce, connect and cap the opposite end? Series or no series basically, and still use 2 1/2 on the two branches that feed the pairs of jets?
Here is a pic of the old setup.
So looking at this jet I'm not sure it's the same kind you have and I don't know exactly what you mean by venturi tees. Do you mean where the pipe comes down from the air line loop to the jet, and would that apply to the kind of jet SpaDepot suggested? If it did, then the air line would come down off the loop, reduce, go into the air tube on the jet, and then I would block the other side of the jet's air tube. This jet looks like it was made to be connected in series, like my old plumbing.
Is the Spa Depot recommendation the best replacement jet for me? or do you recommend another? I can cut the hole in the spa wall bigger than 2 1/2" if necessary. And the same issue as with the water if I use these jets, run the air lines in series, reducing from and expanding to 2 1/2, or like you, in parallel?
 
Re: What size pipe to plumb my pool and spa?

I am not seeing any pictures.

But take a look again at the picture I posted earlier of spa plumbing. There many others on the web.

Gunite spa plumbing - Google Search

Here is a picture of a couple different venturi tees. The plumbing depends on the type of tee used.

venturidetail-640x233_clr2.jpg
 
Re: What size pipe to plumb my pool and spa?

Bummer you didn't get my pictures. It works if I drag them from the manufacturer's site window.
10-5100-WHTx-700x700.jpg

I posted one pic of my spa and one of the fitting Spadepot recommended to replace existing jets. You may not see my spa pic. It's a jpeg I drug from my desktop, but they look like an older version of the one above. So how's the best way to hook those up or should I change them out for a different style. I would only do that if the new style works better. Thanks again. I'll look into the pic problem.
 
Re: What size pipe to plumb my pool and spa?

Those type are meant to be plumbed in series with the loop pipe (water and air). No tee is necessary except where attached to the pipe from the pump. What size pipe does that take? Those tend to come in 1 1/2" size which I think is too small for a loop but I would definitely use a full loop if you go with that small of pipe. I believe they used something similar in this pic:

CIMG2026-2.jpg
 
Re: What size pipe to plumb my pool and spa?

There are a lot of choices for jets and jet sizes, it really depends on what you are trying to achieve.

The jets they recommend are 3/8" jets that require 13 GPM each which is a very common size for a jet. Larger jets such as 7/16" require higher flow rates (25 GPM) for the same pressure but also creates a larger area of impact on the body. Smaller jets, the opposite.

The advantage of the jets they are recommending is that they are probably easier to install because they don't require many extra fittings. However, they are more expensive too. As long as you are planning only 4 jets, you can make those work better by teeing the supply line mid-way between the four jets and downsizing to 1 1/2" at the first jet in each branch. Then use 1 1/2" pipe between the two jets in each branch. This should help to minimize any differences between the jets.

But with only 4 jets and 56 GPM total to the spa, you probably really only need 2" pipe for that but 2 1/2" would not hurt anything either.
 
Re: What size pipe to plumb my pool and spa?

Someone in one post that I can't find said put two drains in my spa. Is that for safety or flow? I'm running 3" suction from drain to pad and 2 1/2" return from pad to spa. I've only got 4 jets drawing 13 gpm each. I don't think I need two drains for flow, yes or no? It only has one now, in the center of the floor and a skimmer as well. It's an old octagon spa.
 

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

Well I don't want anyone getting stuck and I want strong flow so maybe I should install an extra drain. Yes, no, and if so should it be on the wall rather than the bottom, or does it matter? Not much room on bottom. Also I have an old hayward SP1035 drain that is 1 1/2" and I need to replace it. I think it should be 2" but with two drains should they both be 2", if I go with two?

"But with only 4 jets and 56 GPM total to the spa, you probably really only need 2" pipe for that but 2 1/2" would not hurt anything either."

Mark, I don't know if you meant for both vac and return lines or just one, or which one? I was planning on 3" suction and 2 1/2" return, but I've been reading your old posts to others and now I'm concerned that 3" suction and 2 1/2" return may not give me enough head loss. Please tell me what is the optimal size pipe from pad to spa (return) and from spa to pad (suction), now that I can give you a clear picture of my situation.

Four 13 gpm jets = 52 gpm + a waterfall at the same time of about 25 gpm so 77 gpm

The jets are the stacked 1 1/2" HydroAir 10-5100s so I will T equally spaced from the jets, use 2" to the first set of fittings and you said reduce there to 1 1/2 and continue 1 1/2 to the last set of fittings. Question: Would I gain anything as far as the last pair of jets being as strong as the first by expanding up to 2" to get to them?

Waterfall is 75' from pump and I calculated about 16' of head loss. I believe that was just the waterfall, not combined with the spa.

The waterfall is on it's own 2" line, valved from the pad, before the heater, and drains into pool.

Spa is a straight line from the pad, about 33' from the heater and pump.
I plan on 1 vs Inteliflo Pump going into a Hayward 4800 DE Filter, Pentair MiniMax Heater, and probably a Pentair SWG, and automating.

(I don't need the pool and spa on at same time.)

As I said, I was planning 2 1/2" return to the T at the spa and 3" suction out of the drain(s) and skimmer to the back pad. Now that you have all this info in one place, what size pipe is optimal to and from the spa, to give me very strong jets and have enough head loss for the vs pump? Please consider two scenarios, one with the waterfall valved in so both are running, and one with it valved off, so it's only the spa running. Thank you so much.



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

Mark, I don't know if you meant for both vac and return lines or just one, or which one? I was planning on 3" suction and 2 1/2" return, but I've been reading your old posts to others and now I'm concerned that 3" suction and 2 1/2" return may not give me enough head loss.
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The spa jets have a lot of head loss so that is not a concern. 3" is definitely overkill and not needed. Even 2 1/2" you really don't need. But like I said before, it wouldn't hurt anything either. And for a spa, keep the suction and return same size.


Four 13 gpm jets = 52 gpm + a waterfall at the same time of about 25 gpm so 77 gpm
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How are you going to do that without loosing hot water from the spa? If you want the waterfall at the same time as the spa, you really need a separate waterfall pump. Or does the waterfall go back to the spa?


Would I gain anything as far as the last pair of jets being as strong as the first by expanding up to 2" to get to them?
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No because you would need transitions from 1 1/2" to 2" and back which negates any benefit in the 2" pipe. Plus those pipes would have 13 GPM max so not much head loss in that short section.
 
Re: What size pipe to plumb my pool and spa?

Thank you Mark for so much needed information. On the waterfall without taking heated water from the spa, I thought teeing off the line between the filter and heater and valving it before it goes to the waterfall would be a way. Yes? The waterfall goes into the pool, not the spa. It wouldn't be heated.
 
Re: What size pipe to plumb my pool and spa?

When in spa mode, the pump suction is drawing from the spa which has heated water. Doesn't matter if you tee it before the heater, the pool stills get heated water from the spa. Plus it would drain the spa eventually.

To keep the pool and spa water separate, you need two pumps. Waterfall draws from pool and returns to pool. Spa draws from spa and returns to spa. No other way to do it other than not run the waterfall with the spa.
 
Re: What size pipe to plumb my pool and spa?

So if the waterfall has its own pump can I come off the existing (not yet buried) 2 1/2" pool suction line (before it gets to the spa/pool valve) to feed it.

If both pool and waterfall are on:

If i can come off the existing suction line, should I
(1) use a wye (pool suction line runs 45 degrees to the pump room), reduce down to 2", then valve it before it gets to the waterfall pump, or
(2) use a valve at that pool/waterfall suction junction that adjusts percentages of flow to the pool pump and waterfall pump, or
(3) just come off the 2 1/2" pool suction line with a reducing wye, no valve before the waterfall pump, but regulate amount of flow in the waterfall system with a valve after the waterfall pump?

Is the danger cavitation because the pool pump isn't getting enough compared to it's returns, and the same would have to be considered for the waterfall pump.

If the spa is on, the pool is not, so I don't think cavitation of the waterfall pump is an issue then. Both pumps running, one for spa and one for waterfall, and systems are isolated.

If both pool and waterfall are on:

Thinking of the waterfall pump:
1. It's 75' of 2" pipe to the 4' high waterfall that I figured to be about 16' head loss from pump to waterfall.
2. The 2 1/2" suction from the pool skimmer to the pad is about 53 feet - a 90 out of the skimmer box, a 45, a wye, and about 10' of pipe (could still be
2 1/2") to the waterfall pump where I would use a couple sweeps to get it to the waterfall pump.

Thinking of the pool pump:
1. I'll be running it at low speed probably 24/7 (except when I'm using the spa, when it powers the spa and is mostly isolated from the pool (the spa overflows into pool so I'd set the pool return valve to give a little to the spa and most to the waterfall. It's ok, even good, if water overflowing from the spa heats the pool a bit.
2. I have about 10' of 2 1/2" pipe out of heater, wyeing to two runs of 2" return pipes, one 75' long, feeding four returns, and the other 45' long, feeding three returns. The return fittings have 1/2" eyes.
3. The suction line to pool pump is about 35' of 2 1/2" pipe from skimmer to pool pump.

The general question is if I want the pool and waterfall pumps working at the same time, is possible for me to run both of them off the pool suction line, keeping in mind I calculated 25 gpm on the waterfall and the pool pump will be running on low? Does this seem possible with my particulars. (I'm going to automate so the valve turning will be automatic.) I'm trying not to change one of my returns to a dedicated waterfall suction line, since the return I'd use is already plumbed. If I can tap into the pool suction line that might be easier. Thanks for all the attention it will take to consider this and let me know your opinion.
 
Re: What size pipe to plumb my pool and spa?

You would be better off having a separate suction line for the waterfall if possible. You technically have way more return lines then necessary anyway, why not turn one of those into a suction line for the WF? A suction wall port is acceptable and you can find anti-entrapment covers for those as well.

Also, I would stick with standard sch 40 90 ELLs and TEEs. Wye's and sweeps are typically DWV fittings with shorter glue skirts and can more easily fail than schedule 40 PVC fittings. Plus they really don't help much anyway. The risk of failure is far more important.

You can share the suction line between the waterfall and pool pump but you would not want to run the pool pump at full speed while running the waterfall. That could cause cavitation in the main pump. To plumb them together, you would have to have check valves on each of the pump's outlets so that water cannot flow backwards when one of the pumps is off. For the main circulation pump, this check valve could be placed after the filter to keep the check valve clean.


1. It's 75' of 2" pipe to the 4' high waterfall that I figured to be about 16' head loss from pump to waterfall.
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How did you get to this? 75' of 2" pipe at 25 GPM is less than 1' of head loss. The elevation rise is 4' or a total of 5' of return head loss.
 
Re: What size pipe to plumb my pool and spa?

I might do a separate suction line for my waterfall. I'm looking into converting one return. The one I would use is the one old copper returns I didn't take out. It's not perfectly round and it would be a job to get a fitting on it, even just chipping deep enough around it and if I do I might ruin the pipe and not be able to get anything on it. Oh well.

On the head loss I don't remember how I figured that, maybe included the spa or whole system, but it's wrong. I just plugged it into the freecalc.com calculator and got 1.1 foot of head loss from pump to waterfall, then add the 4 ft, so 5 foot, and you're right.

Also replacing the 5 short radius 90s with long radius 90s didn't make a difference for line friction in their calculations at 25 gpm, so you're right again:)

So, can I use any of my three 1 HP pumps exclusively for the waterfall if it's drawing 25 gpm? I have an old Hayward dual speed MaxFlo as well as the two in my signature.
Thanks.
 
Re: What size pipe to plumb my pool and spa?

Our spa is always ready to use year round, cost very little to heat and circulate water 24/7, and it has two separate 5 hp pumps for very strong jet action. You have to hang on when you turn on the venturi action or the jets can blow you off the seat. Without the venturi some of the jets will move you out of your seat. That is real massaging action. :wink:
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Alice (GeekGranny),
I'm renovating my pool and spa in California and would be very interested in your spa equipment and plumbing since I want strong jets. Two 5 HP pumps?!! Wow! How many jets does each handle and what kind of jets, and do you have an air blower or not?
Thanks.

Also, Mark,
Thanks for chiming in since I want to do pretty much what you said was possible, have a spa overflow ability, but valve for how much mixing I want, and when. I think the heater would keep it real hot, even with the overflow on, since the incoming pool water would be mixing with a larger amount of hot spa water even before it goes through the pump, filter, heater, and back to the spa.
Thanks
 

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