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Thread: Need to change plumbing from copper to PVC, get rid of drain

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    Need to change plumbing from copper to PVC, get rid of drain

    Hello everyone,
    I have a leak in the pool plaster/shell and also leaking suction line. I have a salt system and original 1970' copper plumbing. I decided to replaster to pool and also fix the plumbing.
    My pool loses about 0.5-1" per day and that requires me to add water 1.5 hours of full flow water to the pool every week. This is getting me a $400 water bill, and nightmare trying to control the chemistry when i always add fresh water and lose chemicals...
    Received an estimate to change the whole existing plumbing to PVC. That includes 4 returns, new skimmer, vacuum line and a 3 feet under the surface suction "drain", that also requires cutting concrete that i have around the pool. All plumbing for $2200.
    My question is about the main drain that the contractor want to eliminate. He is saying it is not really needed as i could use the vacuum line and the automatic cleaner to do the "drain function". His reasoning is that if I want him to plumb a new drain line too, he will need to cut into the pool shell, install new PVC, have a re-bar work done as the shell is now compromised, then needs a shot-crete job done to fill the concrete. He claims this extra would cost me another $5000 and really doesn't make sense. He will basically shut the old main drain, and they would replaster it so it would not even be visible.
    The suction will be done using a new skimmer, a 3 feet under the water level "mini drain", and the vacuum auto cleaner that i would connect to the special line. He will also provide a 3 way valve to control the suction plumbing.

    What is your take one it, does it make sense? Can i really be happy about getting rid of the main drain, getting brand new plumbing and no leaks for $2200?

    btw: the re-plaster job with replacing 150 lf of tile will run me an additional $5300.

    ============================================================ =========================
    40' x 20' gunite, pentair IC40 SWG, 10 Fafco solar panels, 60 sf Pentair DE filter
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    polyvue's Avatar
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    What is your take one it, does it make sense? Can i really be happy about getting rid of the main drain, getting brand new plumbing and no leaks for $2200? [T]he re-plaster job with replacing 150 lf of tile will run me an additional $5300.
    I can offer my opinion, provided from one who is not in the construction or building trades, and it is this: Sounds like a perfectly reasonable solution. I'm not sure there is any intrinsic happiness involved in having or not having a main drain. It would provide for better circulation in that area of the pool, but it doesn't have to be located dead-center deep end to be effective for turnover.

    In your description of the proposal I was looking for pipe dimensions and a pump specification but didn't see either one. What diameter is the existing copper pipe? What size PVC pipe does this proposal include for the 4 returns and the suction (skimmer, vacuum, sub-surface drain) pipes? Does the proposal include (or did the estimator mention) an estimate for total head feet or GPM/flow? etc Would want to match to pump and filter with the PVC ID (for both suction and return runs.)

    Finally, est. price of $2200 / $5300 sounds about right to my ears.... OK now we'll see what the real experts have to say about this!
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    I have a leak in the pool plaster/shell and also leaking suction line
    Have you definitively identified the source of the leak? Suction side leaks (water leaks...not air) are not particularly common unless it's around the skimmer.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    A friend of mine has never used his main drain and keeps it shut at all times. He uses an auto vacuum. It has not seemed to make any difference.
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    My uninformed opinion is that the value of a main drain depends on the depth of the deep end, and on the depth of your local water table. If the water table is an issue then you need a pressure relief valve and you might as well have a main drain at the same point. If it's not, and the deep end isn't so deep (like 6') then it's reasonable not to have one.

    Like polyvue, I am wondering about the pipe diameters. From all I've read on the forum, 2" is a vast improvement over 1.5", even if your fittings are 1.5" you should run 2" pipe and use adapters at each end.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    polyvue,
    The estimator didn't mention the GPM or any number.
    My existing suction and return line is 2" copper. The new PVC would also be 2".
    I think the vacuum line will be 1.5".
    I'm not sure if copper and PVC with same trade size are equal in ID....
    I figure that since I'm replacing 4 returns for the same 4 return with similar size pipe, and the same thing with the single skimmer like the existing one, i should be fine...unless the design of my pool was wrong from the get go. Do you think I should go with 3" PVC or something? I will look today at the pump and provide he HP, GPM figures.

    duraleigh,
    I had a leak detector company ($300), and they checked it with gas. The identified a leak in the elbow on the copper line suction side just under the small concrete slab, where the pool equipment is sitting on. He did mention that during operation, it will simply suck air (as you can see from bubbles coming from the returns....) but when pump is off...that point at the height of the pool line or maybe 6" lower, so water will leak out...
    The crack in the shell was identified by him and also by me using dye.

    PaulR,
    The pool is almost rectangular with rounded floor. Half of it is about 3 feet deep, and other half includes slope down and the deepest point about 9.5-10 feet (there is also a jumping board)
    I'm not sure about water table, I do know that the pool was empty for 3-4 month when we bought the house. Also, the estimator said i don't have a hydrostatic valve.
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Laker,

    I understand about the copper pipe leak. Are you saying the other leak is in the pool structure itself? How are they proposing to stop that?

    What I'm thinking is that leak in the pipe can probably be fixed for $200 or less. I may not yet understand about the leak in the shell so I'll hold off until you respond back.

    On a pool that deep, I would be tempted to make use of a main drain that seems to be functioning. (is that right?) and make the necessary repairs but not be in such a big hurry to replace undergraound plumbing that is appaerntly only broken in one (?) spot.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    One contractor claimed that all needs to be done is re-plastering....
    Another one said that he could only know for sure after the old plaster is fully removed and the concrete shell is exposed. Based on the crack size (width) of about 1/16" at most (2 feet long), he said it will be reinforced with more re bar apply "totalseal" and let it dry for 2 weeks before plaster. He suggested it would cost me $800.

    The leak detector guy claimed that since the leak under the equipment slab is so big, he cann't tell me if there is another leak in that line.... It could be that the remaining is good. But since I'm about to invest about $5300 in re-plastering, i would hate to find out that i have bad plumbing or bad leaking drain...
    I can bypass that leaking elbow that is under the slab, and connect it directly to the pump.

    The issue that wasn't addressed here is that i have a salt system in this pool and the pipes are copper...not too good of a combination. The salt system installed around 2006. The pool and the original plumbing from 1970.
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    I have a much better picture now. I can't help with the salt and copper combination but I have a feeling it is no big deal. Whether or not the break in the line is larger than expected is a problem. Usually, pipe breaks occur from settling. If you can see that the decking has obviously settled at that point, then that's probably the only point but, like you said, no guarantee.

    You obviously have a major issue that could be fairly easy to fix or maybe very troublesome. Keep us posted.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    One contractor claimed that all needs to be done is re-plastering....
    Another one said that he could only know for sure after the old plaster is fully removed and the concrete shell is exposed. Based on the crack size (width) of about 1/16" at most (2 feet long), he said it will be reinforced with more re bar apply "totalseal" and let it dry for 2 weeks before plaster. He suggested it would cost me $800.
    The truth is that until the pool is drained and the plaster is removed, it is impossible to see if the crack is structural or cosmetic, and nobody is able to provide a cost until that is factually determined. I see "cracks" daily and they are often nothing, but it does take draining and chipping to see what is really happening. Are you in expansive soil? Have you put any dye near the "crack" to see if it is puling water?

    The main drain in the pool bottom is not required (I usually do not put them in at all in the pools I build anymore). When pool cleaners became more efficient, the need for main drains as a way to suck up debris became all but obsolete. Most often the drain was filled with junk and didn't work anyway, or there was not enough suction on the bottom (it was mostly at the skimmer) to really do much. The pool cleaners have now become "moving main drains", and with a dedicated wall fitting and the ability to regulate suction from the cleaner and the skimmer, flow issues are usually not a consideration.

    PM me if you want an unbiased (with nothing to gain!) answer on your plaster! Sounds like you may be in S. Calif from your screen name! I am in San Diego so I should have a pretty good handle on your area and what the pricing should be for the work.

    Bruce

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Thanks Bruce,
    Indeed both myself and the guy from leak detector used dye, and i noticed that it is pulled into the crack...
    Funny thing is the couple of weeks ago, there was even a small green piece of some sort of grass or weed that started to grow from there. (keep in mind this is about 10 inches under water level)
    The crack itself starts from the tile and goes down about 2-3 feet where it really becomes small (cosmetic) on the floor. That is on the shallow end of the pool 2-3 feet deep.
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    The estimator didn't mention the GPM or any number.
    My existing suction and return line is 2" copper. The new PVC would also be 2".
    I think the vacuum line will be 1.5" [...]
    I figure that since I'm replacing 4 returns for the same 4 return with similar size pipe, and the same thing with the single skimmer like the existing one, i should be fine...unless the design of my pool was wrong from the get go.
    Do you think I should go with 3" PVC or something? I will look today at the pump and provide he HP, GPM figures.
    20x40 x10 ft. is a pretty good sized pool. Are you planning to replace the DE filter and/or main pump? Either way, knowing the pump make/model and BHP, current filter PSI and estimated GPM may be important to right-sizing the replaced PVC lines.

    I would want to know pump/filter/gpm specs. before recommending 3" PVC runs, but if this were my $7.5K investment and pool, I'd run the numbers and see if it wasn't possible. I built a 14K IG pool & spa about 2 yrs ago and had to press the builder to upsize all PVC to 2" (he liked 1.5 for some reason); but now I know I could have installed 3" suction and 2.5" return pipes.

    You have a rare opportunity to economically (for little add'l cost) upsize your suction and return lines. Even if you elect to up-size the suction side pipes only, you could see some improvement in flow and reduced suction head loss.

    Example -Suction side -Increased diameter PVC pipe runs

    Skimmer 2" → 2.5"
    Sub-surface 2" → 2.5"
    Vacuum 1.5" → 2.5"


    The chart below demostrates how head loss falls off as the pipe diameters are increased; also, an excerpt from the discussion on pipe sizing in Pool School.

    For a standard plumbing system with a filter, heater and without solar, water features or cleaners engaged, the suction head loss can be approximated by the following:

    Suction head = 50% of return head for 2" suction and 2" return pipe
    Suction head = 30% of return head for 2.5" suction and 2.5" return pipe
    Suction head = 22% of return head for 2.5" suction and 2" return pipe
    Suction head = 17% of return head for 3" suction and 3" return pipe
    Suction head = 14% of return head for 3" suction and 2.5" return pipe

    Pipe Sizing

    Generally, the bigger the better although too low of head loss can be a problem with pumps. They tend to get noisy if the head loss is too low. However, it is much easier to add head to plumbing via restriction valves then it is to reduce head after the plumbing is installed so it is best to err on the side of too little head loss.

    Also, it is a good idea to use slightly larger pipes for the suction side than the return side since most pumps prefer higher head loss on the return side than suction side. If suction side head is too large, the pump will start to draw in air from the pump lid or valves and may even start to cavitate if the suction loss gets too high.
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    polyvue,
    Thanks for the info on the sizing issue. I have been out of town and only today take a look at the pump to provide you with the exact HP/GPM of it.
    What i can tell you today is that i have a DE filter from Pentair (SMBW 4060) that is 58 sf, 116 GPM.
    Also, I have a solar system that has 11 FAFCO panels (12 feet high each), that is plumbed using 2" lines. So Do you think up sizing the new return line more than 2" will give me any benefit ? (the solar is 2") ?
    Do you think i should up size just the suction line? The vacuum cleaner are using 1.5" i think, so how upsizing this line to say 2.5" will benefit?

    Also, when i say 2", i mean 2" ID (internal, 2.5" OD)
    from what i checked 2" is very common and you can find it in home depot, 2.5" not...so it will be double the price...also the valves etc.
    Do you really think it will give any benefit as the pump, filter, etc are all 2"....
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    polyvue's Avatar
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    Thanks for the info on the sizing issue. I have been out of town and only today take a look at the pump to provide you with the exact HP/GPM of it.
    What i can tell you today is that i have a DE filter from Pentair (SMBW 4060) that is 58 sf, 116 GPM.
    Also, I have a solar system that has 11 FAFCO panels (12 feet high each), that is plumbed using 2" lines. So Do you think up sizing the new return line more than 2" will give me any benefit ? (the solar is 2") ?
    Do you think i should up size just the suction line? The vacuum cleaner are using 1.5" i think, so how upsizing this line to say 2.5" will benefit?

    Also, when i say 2", i mean 2" ID (internal, 2.5" OD)
    from what i checked 2" is very common and you can find it in home depot, 2.5" not...so it will be double the price...also the valves etc.
    Do you really think it will give any benefit as the pump, filter, etc are all 2"....
    I understand the price concern but don't have enough information yet to know how to articulate a cost/benefit analysis. When you're able to get the pump info, will want to know make / model, Horse Power (HP) and Service Factor (SF) (---or Braking horse power BHP). Anything you know beyond that, such as GPM for your system, normal filter PSI (when clean) would be helpful, too. At that point I'll be in better position to try and answer the sizing question with a better chance of being right!

    Also, please keep in mind that I'm not pretending to be a hydraulics expert. I have had a keen interest in this area, and I'm learning along with you and others. Whatever I think, the decision on how to proceed is yours. If I, along with others, make suggestions that in the end help you drive this to a good outcome, that's a win-win. And, not to worry, our resident plumbing "mafia" read these posts... if you have doubts, just post a message stating that you're planning to install a 5 HP pump with 1/2" flex tube on suction & return!
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
    __
    View of spiral galaxy in Ursa Major NGC6217 - Hubble Telescope 2009

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    Re: Need to change plumbing from copper to PVC, get rid of drain

    OK,
    So the pump I have is a American/Pentair Ultra flow with Magnetek 1.5HP full rated with 1.47 SF (that makes it 2.2 effective HP, right?)
    It has 9.6-8.8A draw and rated at 208-230V.
    When i switch the solar off, and with a clean DE filter, my pressure is about 10-12 PSI. When turning the solar on, pressure would rise to about 20 PSI, but i think that i have some debris in the line probably the panels are somewhat clogged, and i would need to clean them up during the pool remodeling. I remember the pressure was rising 5-6 before. (I had a bad DE grid, that passed leaves and DE into the solar....so i guess some of that is in the lines, and "helping" to increase the pressure.
    btw: a 3rd contractor has suggested to use 1.5" suction line and 1-1.5" on the return lines. When i asked why, he said that the returns are connecting to a 3/4" line anyways, so he thinks 1.5" is sufficient and would not see why i need 2"...(my existing copper lines are 2"...)

    I have also posted an (somewhat not related) issue with correct placement of the 3 way valve in a solar system.
    "http://www.troublefreepool.com/solar-system-correct-routing-of-return-line-3-way-valve-t17995.html"
    solar-system-correct-routing-of-return-line-3-way-valve-t17995.html
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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    polyvue's Avatar
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    OK,
    So the pump I have is a American/Pentair Ultra flow with Magnetek 1.5HP full rated with 1.47 SF (that makes it 2.2 effective HP, right?)
    It has 9.6-8.8A draw and rated at 208-230V.
    When i switch the solar off, and with a clean DE filter, my pressure is about 10-12 PSI. When turning the solar on, pressure would rise to about 20 PSI, but i think that i have some debris in the line probably the panels are somewhat clogged, and i would need to clean them up during the pool remodeling. I remember the pressure was rising 5-6 before. (I had a bad DE grid, that passed leaves and DE into the solar....so i guess some of that is in the lines, and "helping" to increase the pressure.
    btw: a 3rd contractor has suggested to use 1.5" suction line and 1-1.5" on the return lines. When i asked why, he said that the returns are connecting to a 3/4" line anyways, so he thinks 1.5" is sufficient and would not see why i need 2"...(my existing copper lines are 2"...)

    I have also posted an (somewhat not related) issue with correct placement of the 3 way valve in a solar system.
    "http://www.troublefreepool.com/solar-system-correct-routing-of-return-line-3-way-valve-t17995.html"
    solar-system-correct-routing-of-return-line-3-way-valve-t17995.html
    I've heard of intentionally adding head to a system by reducers but I'm not sure that downsizing the suction/return lines on a system that seems more or less right-sized with a strong pump is the right way to go. But I think, worse case, you stick with 2" piping throughout. I believe that reducing the diameter of an entire length of a pipe will add friction head even if the outlet is 1 or 1 1/2". Thanks for posting the PSI and pump spec (all seem good for your system, off hand.) I'll try to do some back-of-the-envelope calculations tonight and look at your other thread, then post back what I think current TDH is... that will give you at least one alternative view.
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    polyvue's Avatar
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    I apologize for not posting back sooner... started and stopped calculating Total Dynamic Head a few times until I realized that more info is needed (length of pipe runs, among other things) and not sure what your level of interest is at this point in upsizing the pipe in the new runs. Though I can't tell you with certainty that increased suction side pipe diameters will significantly contribute to lower TDH, that is certainly my impression from calculating my own system's TDH and from reading the information contained in this forum. Another member earlier posted a document by Hayward that I always thought was a great short-hand method to determine pump and/or filter size, so I include this link and others that I think are worthwhile. The 2nd link not only provides a reasonably detailed overview of determining TDH but contains links to other sites with more technical data. Though I've read all of this material at least once, I'm hardly an expert. Great to have as reference material, though. Post back if you're still interested in my crib notes regarding TDH.

    http://www.haywardnet.com/pdfs/Pump_filter_sizing.pdf

    hydraulics-101-have-you-lost-your-head-t915.html


    http://poolplaza.com/pool-pump-sizing-2.shtml

    http://www.engineeringtoolbox.com/press ... d_404.html
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Quote Originally Posted by Laker4ever
    OK,
    So the pump I have is a American/Pentair Ultra flow with Magnetek 1.5HP full rated with 1.47 SF (that makes it 2.2 effective HP, right?)
    It has 9.6-8.8A draw and rated at 208-230V.
    When i switch the solar off, and with a clean DE filter, my pressure is about 10-12 PSI. When turning the solar on, pressure would rise to about 20 PSI, but i think that i have some debris in the line probably the panels are somewhat clogged, and i would need to clean them up during the pool remodeling. I remember the pressure was rising 5-6 before. (I had a bad DE grid, that passed leaves and DE into the solar....so i guess some of that is in the lines, and "helping" to increase the pressure.
    btw: a 3rd contractor has suggested to use 1.5" suction line and 1-1.5" on the return lines. When i asked why, he said that the returns are connecting to a 3/4" line anyways, so he thinks 1.5" is sufficient and would not see why i need 2"...(my existing copper lines are 2"...)

    I have also posted an (somewhat not related) issue with correct placement of the 3 way valve in a solar system.
    "http://www.troublefreepool.com/solar-system-correct-routing-of-return-line-3-way-valve-t17995.html"
    solar-system-correct-routing-of-return-line-3-way-valve-t17995.html
    I can run some number on the head loss model I have but I would need at least the following additional information:

    Length and number of runs for the suction side and pipe diameter (i.e. is there a separate run for each suction port, skimmer, main drain pair...)
    Length and number of return runs and pipe diameter
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  19. Back To Top    #19
    polyvue's Avatar
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    Aug 2009
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    Sacramento, California USA
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    Re: Need to change plumbing from copper to PVC, get rid of drain

    Mark (mas985) was kind enough to respond to several questions I sent him via PM regarding pipe sizes and their potential contribution to total dynamic head. Though asked in reference to the project Laker4ever has undertaken, the questions could be asked about any system. The exchange may be of value to those who, like me, have a tentative understanding of this process.

    Quote Originally Posted by mas985

    Quote Originally Posted by polyvue
    Mark,

    In this thread, Laker4ever is preparing to replace existing 2" copper runs with 2" PVC. I suggested that he might be able to achieve a performance boost by upsizing some or all of these to 2 1/2" -- especially on the suction side.

    One contractor, in particular, challenged this notion...
    a 3rd contractor has suggested to use 1.5" suction line and 1-1.5" on the return lines. When i asked why, he said that the returns are connecting to a 3/4" line anyways, so he thinks 1.5" is sufficient and would not see why i need 2"...(my existing copper lines are 2"...)
    • 1) Am I wrong to think that downsizing these runs from 2" to 1.5" will add friction head, regardless of the connections?

      Yes smaller diameter pipe will always add head to a plumbing system vs larger diameter pipe. However, as a percent of total head, it may or may not be that impactful. So sometimes it doesn't pay to have larger pipe but you have to look at the whole design to make a determination.

      2) Is it strictly necessary to calculate system TDH when estimating modest increases in pipe diameter to improve flow?

      For planning, yes the only way to get flow rates from the pump is to know the head loss in the plumbing. However, calculating TDH with any level of accuracy is very difficult unless you have a few calibration points to work with. There are too many variables and unknowns to get it very accurate. So generally I recommend a combination of calibration and modeling to get close to estimate. Since I have fully calibrated my pool's plumbing system, I will often use that as a proxy and modify the design parameters with those of the target pool plumbing. So for factors that are unknown, I simply use the calibrated factors from my pool. This has worked fairly well in the past modeling other pool systems and I can usually get fairly close with this method.

      3) Is there a downside to installing an oversized suction pipe for a dedicated vacuum cleaner line --- 2" rather than 1.5", say?

    • No downside, as a minimum I would use 2".

    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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  20. Back To Top    #20

    Re: Need to change plumbing from copper to PVC, get rid of drain

    Mark,
    I have a single suction line of 2" (copper) that is coming to the pump. There is a Tee under the skimmer that connect the drain and the skimmer into the single line to the pump. Total length from main drain to skimmer is apx 15 feet. Length from the skimmer to the pump is about 16 feet. (the distance is relatively short as the equipment pad is close to the skimmer)
    The returns are fed using 2" copper that runs a total distance of about 70 feet feeding 4 return outputs. Most of it underground so it might transfer to lower size under the concrete. The line is feeding the return in series, I could clearly feel how the first output (closest) to the pump has the highest pressure and the last had very low pressure.
    I have 3 returns on the side of the pool, and 1 on the other side of the skimmer.

    Is there any thing else needed?
    _________________
    35k gal 850sq ft french gray plaster, Jandy JEP1.5HP ePump, Pentair 60sq DE filter, Pentair Intellichlor IC40, 10 Fafco sunsaver 12'x4' panels with Goldline GL35. Laars lite 325k BTU NG heater, Hayward Colorlogic 4.0 LED light. Plumbing: 2" PVC, No main drain, four 1" returns, 1 skimmer with 2 wall drains, one 1.5" suction cleaning port.

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