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Thread: Upsize Pump And/Or Piping?

  1. #1
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    Default Upsize Pump And/Or Piping?

    I would appreciate input from the collective wisdom on how best to fix a pool pump capacity problem.

    15,000 gallon inground pool.

    Hayward SuperPump, 2-speed, 1.5 hp, 230 volt, 13-14 years old but motor recently rebuilt. Pump is located approximately 3-4 feet above water level.

    Water feature height is approximately 3 feet above water level.

    All plumbing, including inground, is 1.5 inch.

    Suction side: Three 1.5 inch pipes (main drain and 2 skimmers) "T" into a sort of manifold

    Mechanicals: Pump, Tagelus TA-60 filter (24") with zeolite filter media, heat pump, Jandy check valve, chlorinator

    Return side: *single* 1.5 inch pipe for two returns and 1.5 inch pipe to water feature (valve normally partially closed)

    The problem:

    Heat pump was installed last year. It had to be located 30 feet away from the pump. Total pipe run is around 60 feet, including several 90-degree bends plus the heat exchanger itself.

    Last year, after adding the heat pump with its extended pipe run, the system performance was marginal with the pool pump running at low speed. The system was just barely able to run the chlorinator and water feature.

    This year, net of some problems with the filter (long story) the pool pump running at low speed is unable to operate the water feature (can't lift water to that level) or the chlorinator. Even if I resolve the filter problems, system performance will still be marginal.

    Current backpressure at the filter with the pump on high speed is 23-24 lbs., up from 20-21 lbs. last year, and 5-6 lbs. at low speed. With the heat pump on bypass the backpressures are 18-19 lbs. and 4 lbs.

    Options would appear to be to replace the pool pump and/or upsize to 2 inch pipe (note single 1.5 inch underground return, however).

    Thanks in advance for your thoughts and recommendations.

  2. #2
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    Default Re: Upsize Pump And/Or Piping?

    Some additional information:

    I was just told by my local pool store that the low-speed hp rating for 2-speed pumps is pretty much the same, 1/4 hp, regardless of the high-speed hp rating. This would indicate there is no benefit from going to a 2 hp, 2-speed pump. (The Hayward specs on SuperPumps show a higher gpm at low speed with the higher horsepower units, but the same maximum head regardless of horsepower.)

    I have also heard a concern from several sources (including Hayward) that going to a 2 hp pump (or a 3 hp variable speed pump) would risk blowing out some components of my system due to excess pressure.

    Is this one of those "You can't get there from here" problems?
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

  3. #3
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    Default Re: Upsize Pump And/Or Piping?

    The problem sounds like it could be the filter. A 3 PSI rise may not sound like a lot but it is about 7' of extra head. This can reduce the flow rate quite a bit on high and low speeds. So I would focus on fixing that first.

    You might gain a little with larger pipe above ground but your underground pipes are not that bad because you have 3 separate suction pipes that act as a single 2.5" pipe and the two returns act as a single 2" pipe so the plumbing is not that bad. If the long runs to the heat pump are 1.5", that will reduce flow rate quite a bit. Have you considered a heater bypass or do you use it all the time?

    Also, what kind of check valve are you using? Some models have very high head loss at lower flow rates. If you don't know take a picture and post.
    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

  4. #4
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    Default Re: Upsize Pump And/Or Piping?

    Hi Mark,

    Thanks for your reply. I did have some weirdness with the filter this spring. (Due to bad instructions from the manufactureer a 2-part "floc" product might have reacted inside the filter instead of in the pool.) But..........just today I followed a suggestion and compared backpressure with the filter set on "Filter" and on "Bypass/Recirculate." The difference is only 1 lb., which indicates pretty free flow through the filter.

    I do have a bypass on the heater, but we are wimps and use the heater all the time. As noted above, putting the heater on bypass drops the filter backpressure by around 5 lbs. at high speed and 1-2 lbs. at low speed. With the heater on bypass the low speed is able to (barely) operate the water feature and chlorinator.

    The check valve is a Jandy.

    I've wondered if something "changed" in the heat pump during the (North Carolina) winter or spring startup. In the fall I disconnected all the plumbing to the heater and covered all the open ends with tie-wrapped screen to keep critters out. I did use a garden hose to flush the heater this spring, running the water in both directions.

    (We don't close our pool, so the pump was in use - under timer control - all winter.)

    My timer only controls the low speed on the pump, so I'm having to run the pump 7x24 at high speed. I'm now using a robotic cleaner, so I am wondering about changing to a 1-speed motor that the timer/controller could control.

    Seems like I'm having to reengineer the system while holding the inground piping, filter and heat pump constant. Any and all suggestions would be appreciated.
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

  5. #5
    mas985's Avatar
    mas985 is offline Lifetime Member Whizbang Spinner mas985 3 stars mas985 3 stars mas985 3 stars
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    Default Re: Upsize Pump And/Or Piping?

    So just for clarification. Everything was working perfectly fine before you installed the heat pump, correct?

    Also, maybe I misunderstood your first post. The 3 PSI rise in the filter, was that due to the heat pump or something wrong with the filter?

    It sounded like low speed was working ok with the heat pump but then something happened after than and now it doesn't work? I am trying to understand the history.

    Low speed flow rates are going to be half of high speed, so you can't expect all that much out of low speed. While you don't have any lift with low speed (water feature is at same height as pump correct?) the extra head loss in the heater might be enough to reduce the flow rate to a level that is not all that useful.
    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

  6. #6
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    Default Re: Upsize Pump And/Or Piping?

    A few more thoughts after a bit of sleep and a cup of coffee..............

    The 1.5 inch piping for the returns is a single pipe leaving the equipment shelter. It splits somewhere underground. Does that still count as a 2 inch?

    I've been working up some numbers using a Hayward pump sizing worksheet. For an 8-hour turnover I need around 32 GPM. Maximum flow with 1.5 inch pipe and 8 ft/sec is supposed to be 51 GPM. With the water feature I probably want to be at the high end. 24 PSI of backpressure equals 55 ft of head, plus an estimated 12 ft of friction loss on the suction side, yielding 67 ft. of head. This is a little outside the curve for my pump, but I'm getting away with it. (Low speed isn't supposed to be able to overcome more than 18 ft of head, so I'm surprised it works at all with the heater on bypass.)

    I have an inquiry into the (mechanical) controller mfr to see if I can wire it so that the timer controls high speed operation (essentially abandoning low speed).

    Would it make any sense to increase the size of the runs to/from the heat pump to 2 inches, leaving everything else at 1.5 inches? High speed works OK (although the performance curve says it's a bit undersized), and I'm leaning towards giving up on using the pump at low speed.

    Thanks again.
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

  7. #7
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    Default Re: Upsize Pump And/Or Piping?

    I was writing my post while yours came in, so I just saw your post.

    Everything worked fine last year even after installing the heat pump (although low speed was marginal). Something changed over the winter that added 2-3 psi of backpressure. I had thought that the "floc" might have munged up the filter media, but the difference between running the filter on "filter" and "bypass" is only 1 lb.

    Perhaps something got damaged or plugged in the heat pump over the winter. I did cover the open connections with screen to keep critters out. I gravity drained the heat pump (I don't have a shop vac), so maybe there was some freeze damage if there was water left inside. I did use a garden hose to run water through the heat pump in both directions before hooking it back up this spring. Do you thing that might have damaged something? (I'm having trouble getting hold of the heat pump mfr.)
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

  8. #8
    mas985's Avatar
    mas985 is offline Lifetime Member Whizbang Spinner mas985 3 stars mas985 3 stars mas985 3 stars
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    Default Re: Upsize Pump And/Or Piping?

    Let me clarify a few things.

    First, there is no limit to flow rate in pipe. The 8 ft/sec is a recommendation.

    Second, the head loss in the plumbing is dependent on the flow rate. So on low speed, the head loss is about 1/4 of high speed.

    Third, the suction side should have very low head loss since there are three pipes.

    I can calculate the approximate head loss in your plumbing but I need a little more information.

    What is the approximate length of your suction runs?

    For the return to the pool, how many return eyeballs are in the pool and what are their sizes (e.g. 1", 3/4")?

    How many 90s do you have in the heat pump install and overall on the pad equipment?

    What other fittings do you have on the pad?

    With this information, I can determine what the filter pressure should be given your setup and we can see if there might be an issue.
    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

  9. #9
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    Default Re: Upsize Pump And/Or Piping?

    Suction Side:

    Skimmer1 through and including mainfold - estimated 84 ft., 2x45's, 4x90's
    Skimmer2 through and including manifold - estimated 36 ft., 2x45's, 4x90's
    Main Drain through and including manifold - estimated 45 ft. (including pool depth), 2x45's, 2x90's
    Manifold to pump - 2x90's

    Pressure Side:

    Pump to filter - 1x90
    Filter - Tagelus TA-60, 24", zeolite media
    Filter through and including heat pump bypass - 4x90's
    Bypass to heat pump through and including bypass - 3x90's, 4x45's, approximately 30 ft. to heat pump and back
    Bypass to (but not including) manifold - 1x90, Jandy check valve, unused Nature2 cartridge holder
    Manifold to returns - Single 1.5 inch pipe, 4x90's, probably one 90 underground to split between 2 returns
    Manifold to water feature - at least 5x90's

    All piping is 1.5 inch
    All valves are 2 inch valves with reducing couplers

    Returns:

    I am using Heat Snorkels (www.heatsnorkel.com). They each have a 1 inch side jet and a 3/4 inch eyeball. I removed one of the Heat Snorkels and there was no change in backpressure.

    Backpressure Readings - High Speed (See notes below):

    Filter on Filter, heat pump in circuit - 23 lbs
    Filter on Filter, heat pump bypassed - 20 lbs
    Filter on Bypass, heat pump in circuit - 22.5 lbs
    Filter on Bypass, heat pump bypassed - 17.0-17.5 lbs

    Backpressure Readings, Low Speed:

    Filter on Filter, heat pump in circuit - 5.5 lbs
    Filter on Filter, heat pump bypassed - 4.5 lbs
    Filter on Bypass, heat pump in circuit - 5.5 lbs
    Filter on Bypass, heat pump bypassed - 3.5 lbs

    All backpressure readings are with water feature turned off.

    All backpressure readings were double-checked. The 2.5-3.0 lb difference between Filter and Filter Bypass with the heat pump bypassed is notably different than the 0.5 lb difference between Filter and Filter Bypass with the heat pump in the circuit. I don't know if this could represent reaching (or exceeding) the top end of the performance capability of the pump and/or the zeolite filter media having possibly been clogged by the 2-part "floc" product that may have reacted inside the filter due to incorrect instructions from the manufacturer.
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

  10. #10
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    Default Re: Upsize Pump And/Or Piping?

    Hi Mark,

    Have you had a chance to calculate the head on the suction side of my system?

    On the pressure side, I'm thinking that I should add 2-3 lbs to the current top end of 23 lbs when back-calculating the head. As noted above it seems like the extended run to the heat pump might have exceeded the top end performance of the existing pump.

    One of the online pool supply outfits recommended a 1.5 hp one-speed Pentair Energy Efficient Whisperflo pump or a variable speed pump and also changing all the above-ground piping to 2 inch. What is your opinion of these recommendations? Looking at the performance curves for a Whisperflo, and using 75 ft. of head and 50-60 gpm it looks like a 3/4 or 1 hp unit would work, but I definitely don't want to end up undersized again.

    Thanks again.
    15K gal IG pool; 13 yr old 2spd 1.5HP Hayward SuperPump w/ rebuild motor; 24" Tagelus TA-60 filter w/ zeolite media ; heat pump; chlorinator.
    Pump located ~4 ft abv water level; water features ~3 ft above water level; all plumbing 1.5"

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