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Thread: repiping vs another pump

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    repiping vs another pump

    I have a very old pump (I just moved to this house) and I was thinking to get Pentair Intelliflo vs-svrs. But I've read that this pump works best with 2" piping and I have 1.5". I'd like to do as much as I can myself and I was wondering if it's worth it to change the pipes to 2". The pool has a skimmer and a main drain which seems to not work (the main drain) for some reason (I tried to unclogg it with water pressure but no success; I've heard that it's possible to have been blocked intentionally). If I want to change the pipes, do I have to change the skimmer too? And also, do I have to dig all the way under the pool, to get to the main drain? I'm thinking also to change it to salt water, but I'll leave this for another topic. Any comments and suggestions are appreciated. Thanks. alpop
    My pool is inground, it has about 17000 gallons, the filter is DE, and I think is plaster:)

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    Re: repiping vs another pump

    Good question! It would be good to know which pump you have and what HP rating. A lot of pumps made over the last 20 years are very good. I would be cautious about putting anything above 1 to 1.5 HP on 2" plumbing. The intelliflow works best on 24/7 applications.

    As far as your specific plumbing issue goes, I would leave it alone and just use the 2" line and use the skimmer unless you are having clarity problems. A friend of mine has a 1.5" line powering 2 skimmers and a main drain this is clogged. His pool is about 20,000 gallons and it runs well. To dig everything up and re-pipe would cost thousands.

    Get me your pump info and I'll let you know if it is ideal for your situation.

    Lance
    Lance I. Fitzsimmons
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    Re: repiping vs another pump

    My old pump has 1HP. What I would like to know is : is the Pentair Intelliflo vs-svrs going to work well with my 1.5" pipes? Shoud I get it? If not, any suggestions?
    Thanks for your answer.
    alpop
    My pool is inground, it has about 17000 gallons, the filter is DE, and I think is plaster:)

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    Re: repiping vs another pump

    It is too much pump for your plumbing. 1.5" pvc can only handle 50 gpm. I put a 3/4 hp whisperflo on my friends pool with the same situation and it doesn't even fill the strainer completely. A 1/2 or 3/4 hp whisperflo would work great and would give you the lowest demand for electricity. the variable speed pumps are for pools that need maximum power during certain times and can then throttle back during non peak hours in a commercial situation that has to be on 24/7 or for extended periods of the day.
    Lance I. Fitzsimmons
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    Re: repiping vs another pump

    I think y'all are forgetting that the IntelliFlo is a variable speed pump and can be set with a GPM cap or limit (including for priming) so that it does NOT behave like a large pump (3 HP at its maximum). It can absolutely work with 1.5" piping. In fact, if you were to use lower flow rates, you will probably get significant savings since you are losing more with your 1.5" piping today to begin with so running at slower speeds will save you more in absolute terms than someone with a similar setup that already has 2" piping. A comment from Pentair on this subject is in this thread.

    The IntelliFlo is designed to be VERY efficient at lower speeds so will work much better than a 2-speed pump at low speed or even a 3/4 HP pump. It's a more expensive pump, but it shines at energy savings at lower speeds.

    Now there's the question of whether you are getting enough flow rate in your system to begin with so if you were to give us more details about your piping situation, number of returns/inlets, number of skimmers and floor drains, size of pool in gallons, etc. then we can see if you might need higher flow rates in which case it's the piping that could be your bottleneck depending on how it's piped. If you need only high flow rates, then the Intelliflo might not be your best choice.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: repiping vs another pump

    I would agree with Chemgeek. The Intelliflo can be used on any plumbing but you may not always want to run it at full speed with smaller pipe. Even with the largest plumbing, there is probably no reason to run it at full speed.

    However, the Intelliflo may not always be the most cost effective solution although for most situations it has a lower life time cost over a two speed and one speed pump.

    By comparison, an Intelliflo running at 2750 RPM has approximately the same head curve as a 3/4 HP Whisperflo but the Intelliflo uses about 200 less watts to do it.
    Mark
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    Re: repiping vs another pump

    So the Pentair guy says this: Comment by Pentair Product Technician-Ben on June 28, 2010 at 1:40pm
    The pipe size can reduce your potential savings, but it should be fine otherwise. Just remember that this is a 3hp pump at full speed, not good for your pipe size.

    What real savings if any are you going to get when you consider the extra $450 - $500 you will have to shell out for this pump? I'd say if the one you have works keep using it until it breaks.
    Lance I. Fitzsimmons
    www.poolspaparadise.com

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    Re: repiping vs another pump

    Many thanks to everyone who tries to help me. Here is the info requested: There are two returns (I think 3/4" each), one skimmer, one floor drain, about 17000 gallons.
    alpop
    My pool is inground, it has about 17000 gallons, the filter is DE, and I think is plaster:)

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    4JawChuck's Avatar
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    Re: repiping vs another pump

    Sand filter or cartridge?

    If you have a sand filter you need the 3/4-1 HP to effectively backflush the filter, if you have a cartridge you could get away with a 1/2 HP motor and get similar savings as the more expensive pumps but without the higher speeds which make skimming more effective during peak use times and windy weather. Variable speed motors are expensive and the payback period depending on your electricity rate could be years or more, if you plan on installing a spa it would make sense to put in the larger pump. If your pump is working now I wouldn't change it unless there was an issue.

    You mentioned your main drain is non-functional, can you tell us how you tested it? I can't tell my main drain is working by diving down to the bottom of the pool and putting my hands around it but when I set the vacuum control plate to only draw water from the main drain it is working. Do you have a vacuum control plate under your skimmer basket or is your pool configured differently?
    55 Kilolitre in-ground 18'X36' vinyl lined kidney shape, 1HP pump, Jacuzzi 250lb sand filter, RayPak Delta T 200K BTU natural gas heater. New PoolWerks "Blue Diffusion" liner on May 26th-2011
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    Re: repiping vs another pump

    Quote Originally Posted by 4JawChuck
    If you have a sand filter you need the 3/4-1 HP to effectively backflush the filter
    Are you sure about this statement? I have no problem backwashing my filter with a 0.5hp pump.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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    4JawChuck's Avatar
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    Re: repiping vs another pump

    Quote Originally Posted by dmanb2b
    Quote Originally Posted by 4JawChuck
    If you have a sand filter you need the 3/4-1 HP to effectively backflush the filter
    Are you sure about this statement? I have no problem backwashing my filter with a 0.5hp pump.
    Having enough HP to lift/agitate the sand is a consideration, the two installers I have talked to have mentioned having enough HP for the size of sand filter...so there is a relationship between the two hence why you backwash on high speed. I am assuming if the original pump was 1HP his sand filter will be sized accordingly. Not saying it absolutely won't work, just its a consideration to review. All the sand filters I have looked at have design flow rates, they are spec'd for a reason not just for filtration.

    Of course we could always model a sand particle to see what the minimum water flow rate is required to negate gravity to achieve agitation and relate that to a pump HP equivalent if you like. I'm wondering if sand particle surface tension would affect the "stickyness" to adjacent particles and if algae film formation needs to be taken into account...

    JUST KIDDING!
    55 Kilolitre in-ground 18'X36' vinyl lined kidney shape, 1HP pump, Jacuzzi 250lb sand filter, RayPak Delta T 200K BTU natural gas heater. New PoolWerks "Blue Diffusion" liner on May 26th-2011
    Avatar is my pool!

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    Mod Squad Bama Rambler's Avatar
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    Re: repiping vs another pump

    You'd have to account for not just surface tension but also atomic charge of the particular particle and the adjacent particles and also the adhesion created by debris including but not limited to algae growth and also any possible chems (i.e. Floc) that would be in the water. Also if the water were at shock level the specific gravity will be greater than 1 and that will have to be accounted for also.

    Sounds like it's going to take a 40hp pump to back wash any sand filter!!!
    Dave J. TFP Moderator
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    Re: repiping vs another pump

    My filter is DE (it was stated in my signiture).
    alpop
    My pool is inground, it has about 17000 gallons, the filter is DE, and I think is plaster:)

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    Mod Squad Bama Rambler's Avatar
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    Re: repiping vs another pump

    Quote Originally Posted by alpop
    My old pump has 1HP. What I would like to know is : is the Pentair Intelliflo vs-svrs going to work well with my 1.5" pipes? Shoud I get it? If not, any suggestions?
    Thanks for your answer.
    alpop
    I appologize for veering off the subject a bit.

    The VS will work with your 1½" plumbing. The real question is it economical. While a vs would work well, the cost to benefit ration might make for a long payback time. If your power cost is on the higher side it's probably worth it. If your cost is very low a 2-speed would be my choice.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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