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Thread: Pumps life shortened by having more on/off intervals?

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    DaneCE's Avatar
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    Pumps life shortened by having more on/off intervals?

    I did some searching and found a few threads that address run times, off peaks hours, etc.

    Just like everyone else, I'm trying to maximize my pumping efficiency. I have a 15'x30'x52" above ground using a Hayward Pro Series 150 lb. sand filter(unknown age but in good shape) and Hayward Power-Flo Matrix 1 HP pump(3 months old).

    My pool water looks clear overall and all chemical parameters are in check.

    I've been experimenting with multiple on/off cycles trying to keep total daily pump run-time under 8 hours within a 24 hour period. For the past week I've been running the pump starting at 8 AM...on for one hour, off for one hour, totaling 6 hours(8 AM to 7 PM ). Water quality looks good. My next schedule might be on for one hour, off for two, totaling 5 hours (8 AM to 9 PM). I have many small plants/flowers on my pool deck and small debris from this randomly enters the pool. I like to see a clean water surface so having the pump off for several hours during the swimming hours(10 AM to 8 PM) is not good. Two nights per week I clean the bottom with a cheap Baracuda Ranger, overnight (10 hours each).

    If I use a timer schedule with 5 on/off times will this shorten the life of the pump compared to one on/off cycle within a 24 hour period(if total run-time was equal)?

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    Re: Pumps life shortened by having more on/off intervals?

    It's not uncommon for large motors to have to have a specification on time between starts. When a motor starts, it can pull much more current and heat up. If you cycle it often, it can heat up and cause issues. That said, even the large 4160 volt motors I've seen allow at least 1 start per hour and a small pool motor should be plenty fine with 1 start per hour. If at all, the time to be cautious would be when you're flushing your filter and turning the pump on and off everytime you change the valve but I haven't come accross any issues doing that from my reading of the pool world.

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    bobodaclown's Avatar
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    Re: Pumps life shortened by having more on/off intervals?

    I don't think it would have a great effect (minimal) on the motor life. The contacts in the switch(timer) take the brunt of the shock (literally) when switching. Unless your electric rates are metered based on time of day setting it really doesn't matter when you run your pump. You don't mention if you have a SWCG so I'm guessing not. I've got my pump to run in the am for about 3 hours then in the afternoon/evening 3-4 hours. I have to increase my pump run time during the summer to give the SWCG time to produce enough chlorine to maintain the proper level.
    17K Kidney Shaped Pool Concrete (Diamond Bright) Pool, 3/4 hp 2 speed 115V Sta-rite Duraglas PEA5D-180L/P2R5D-181L (Impeller C105-92PS Diffuser C1-216P), 1.5 piping, Pentair CC100 Filter , Heat Siphon 100K BTU Heat Pump Pool Heater, Flow meter Blue White Flowmeter Model No. F-30150P, Hayward Astrolight SP0581N, SWCG CalimarTitanium Edition TE45 , Dolphin Nautilus Plus with CleverClean, Lakeland Florida

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    JasonLion's Avatar
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    Re: Pumps life shortened by having more on/off intervals?

    On/off cycles are not a big deal as long as they aren't all crowded together one after another.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Ohm_Boy's Avatar
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    Re: Pumps life shortened by having more on/off intervals?

    An induction motor, at startup, will draw [typically] five to seven times it's normal run current. There is some heat and stress on the windings when that happens, but it is generally within the design of the motor to handle. That *should* make an argument for less starts, but I don't think that it's an appreciable factor in normal pool pump motors.

    I used to have to maintain ten minutes between starts on motors in the 80hp - 500hp range. Pool pump motors, like Jason said, can handle pretty much whatever duty cycle you demand of them, as long as you give them at least a few seconds between cycles. If you space them a minute or more, it should be okay.

    In other words, if you aren't controlling it with a Morse code key, you should be fine.
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    DaneCE's Avatar
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    Re: Pumps life shortened by having more on/off intervals?

    Hey, thanks a lot guys. I appreciate your comments. It looks like I'm safe to continue experimenting with cycles.

    I'm on my third year with my pool and I don't know how old any of it is(a new to me old house). The reason I replaced the pump is that the old (identical) pump eventually failed to start after I fought with the centrifugal switch getting stuck open repeatedly. Not knowing how old it was, I didn't want to sink any money into repairing it. I have good piece of mind now with a new pump and don't want to cut its life short.

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