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Thread: Time to change the motor...

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    Time to change the motor...

    So finally got the pool opened after diy liner install and found my pump (which was loud last year) is now very loud! Last weekend I spent a few hours determined to rebuild it. I failed! I got it apart but broke three long bolts that hold the motor case together - they were very rusty. The back bearing wasn't bad at all. I couldn't access the front bearing as the two little bolts that hold it behind the faceplate would not budge! They are also very rusty and now stripped - of course! I gave up and put it back together. It still runs but it's really loud!

    Therefore, I'm looking into new motors. I inherited all this stuff about 5 years when I got the house and it appears everything is original since install in 1999. I have a hayward max-flow pump. Wet end looks pretty good - installed new seal when I had it apart this weekend. The motor is magnatek 1 hp with a SF of 1.0, 3450 rpm, threaded shaft, yada yada, all pretty standard... Surprisingly the best deals I see for motors are on Amazon. The one I'm looking at matches everything but says it has a SF of 1.1. Does this matter? I've read up a bit on here and it sounds like SF doesn't really matter and has more to do with marketing...

    Any advice would be appreciated before I get this motor ordered.

    Thanks!
    16 x 32 inground vinyl pool (21000 gallons) (new liner installed 2014)
    Hayward max flo pump w/ 1 HP AO Smith motor (new motor 2014)
    Hayward C1200 cartridge filter (new 2014)
    Hayward H150 heater

  2. Back To Top    #2
    Mod Squad zea3's Avatar
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    Re: Time to change the motor...

    You are correct.
    TFP Moderator
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    Mod Squad jblizzle's Avatar
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    Re: Time to change the motor...

    I would recommend taking the opportunity to upgrade to a 2 speed motor.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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  4. Back To Top    #4

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    Re: Time to change the motor...

    I would like to go 2 speed but not in the budget this year after new liner. Also looks like I may need a new cartridge filter as well - it's developing hairline cracks in the housing and currently has some major leakage. I'm thinking cheap new motor this year (prices I see are between $150-200) and upgrade next year. Unless a 2 speed isn't much more expensive... I haven't looked into pricing them much just assumed they were much more $. Would I need to change anything else if I go 2-speed? Different Impeller?
    16 x 32 inground vinyl pool (21000 gallons) (new liner installed 2014)
    Hayward max flo pump w/ 1 HP AO Smith motor (new motor 2014)
    Hayward C1200 cartridge filter (new 2014)
    Hayward H150 heater

  5. Back To Top    #5

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    Re: Time to change the motor...

    Just saw this one on Amazon: http://www.amazon.com/1-5HP-Speed-Th...+2+speed+motor

    Sounds like it woould work and price is right? Looks pretty generic though...
    16 x 32 inground vinyl pool (21000 gallons) (new liner installed 2014)
    Hayward max flo pump w/ 1 HP AO Smith motor (new motor 2014)
    Hayward C1200 cartridge filter (new 2014)
    Hayward H150 heater

  6. Back To Top    #6
    Mod Squad jblizzle's Avatar
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    Re: Time to change the motor...

    That would work, although you have a smaller impeller so should be able to get a 1HP 2 speed for cheaper.

    You can use the larger motor on your impeller no problem. You will just need to add a switch to select speeds, a household 3 way light switch works well. And a shaft seal which I think you already got.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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  7. Back To Top    #7

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    Re: Time to change the motor...

    That link shows the motor has a toggle switch on the back to change speeds. Yeah main concern is the impeller going to 1.5 horses. You say it's not an issue?

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    Smykowski's Avatar
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    Re: Time to change the motor...

    You can put a smaller impeller on a bigger motor. Never put a bigger impeller on a smaller motor.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
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  9. Back To Top    #9

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    Re: Time to change the motor...

    How does that work with a 2 speed motor then? If having a big impeller on a small motor is bad, what happens when motor is running in low? Isn't that essentially the same concept?
    16 x 32 inground vinyl pool (21000 gallons) (new liner installed 2014)
    Hayward max flo pump w/ 1 HP AO Smith motor (new motor 2014)
    Hayward C1200 cartridge filter (new 2014)
    Hayward H150 heater

  10. Back To Top    #10
    Mod Squad jblizzle's Avatar
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    Re: Time to change the motor...

    No, because the low speed is designed to work like that.
    Putting a larger impeller on a smaller motor would put too much resistance on the motor and make it overheat. Electric motors run at a set RPM, so the motor will run at that speed regardless of the resistance which is why they burn up.

    A smaller impeller on a larger motor will still run at the same speed, but with less resistance so lower here and power usage would be needed.

    A 1HP impeller on a 1.5HP motor will use a very similar amount of power to that of a 1HP motor on the same impeller.
    I just though you might be able to get a 1HP motor for less than the 1.5HP motor ... if not, the 1.5 will work fine.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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  11. Back To Top    #11
    Smykowski's Avatar
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    Re: Time to change the motor...

    Here's the bicycle analogy....

    Imagine you're riding your 10 speed and you have to maintain 75 rpm. Set the gears to the lowest (easiest gear) and pump away at 75 rpm. Perceived effort is pretty low. Easy even. Now crank it up to the highest gear and hold 75 rpm. Much much harder. In this case, you (the pedaler) are the motor, and changing to the higher gear is equivalent to putting on a bigger impeller. With the same size motor but a bigger impeller (same size legs but "harder" gear ratio), you're gonna get burned up pretty quick.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

  12. Back To Top    #12

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    Re: Time to change the motor...

    Ok, think I got it. Thanks for all your help!

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