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Thread: New Motor and Pump Not Fully Priming

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    New Motor and Pump Not Fully Priming

    Im very lost and hoping someone can shed some light on my issue. I have done endless research and spent a little to much money and need some help.


    Issue My AO Smith B2848 HP=1 SF=1.65 Died and ceased.


    A friend of mine had filled his pool in because he was tired of it after 15 years gave me a pump and motor he had just sitting around doing nothing. This pump is a AO Smith 2853 HP=1 SF=-1.25 and is in great shape and came with a SP-3200 Series pump. After re-plumbing the inlet pipe to the new motor and pump and replacing the lid seal and even putting silicone at all of the joints to make sure there is no leaks the pump will not filly prime and will only put out 10psi to my filter.


    Now where things get interesting. There are not leaks of any kind that I can find. Also when I turn off the pump it holds a seal and no water is lost and no extra air comes into the pump. I can then turn on the pump again and it starts working right as it was. Before my pump died it would put out 15psi and the pump would prime with no issue. The Pump was old and didnt look in good shape so I opted for the new pump on the new motor.


    I spoke to a few Pool stores and even had one come out. They informed me that the new motor I got just didn't have the correct amount of power. They informed me to get another 2848 or 2858. So I looked around in my area and a 2858 was local and a good price brand new. After installing the new 2858 HP=1.5 SF=1.5 motor on the Hayward SP-3200 I get the same result that the pump will not fully prime. But now my PSI went up to 15psi. Again when I turn the pump off it holds a seal.

    Other information about the pool. Impeller is clean no debri, Piping is 1.5", only a skimmer no bottom drain, Liner pool, 18,00 gallons, and salt water pool.


    I know nothing about the impellers. Thought it may be that that's why Im now reaching out TFP.
    Thank you anyone for advice.

  2. Back To Top    #2
    Texas Splash's Avatar
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    Re: New Motor and Pump Not Fully Priming

    Not my area of expertise, but I wanted to give this a and ask a couple questions to help get this going for you. The psi comparisons you are referencing, that's from your filter housing correct? If so, I would be careful to judge pump/motor performance solely from that since we know the psi is also tied-into the resistance from the filter media as well. Some people have the same or lower psi readings when their pump is on high or low. My 2HP never goes over 10 psi even when I switch to high ... unless the filter is packed with gunk. So if you were to ignore psi for a moment, how is the water circulation? Is the return jet pressure similar to what you had before the original motor failed?
    - The new pump (wet end) you got from your friend, any chance the diffuser or impeller appear to be damaged or warped? Everything present (seals, impeller ring, etc) as noted HERE? I believe that's the same pump right?
    - Normally we would relate loss of prime to anything from the poolside skimmer to the pump wet-end, to include drain plug and possibly seal plate. But you already stated no water leaks when turned-off. Pool water level good? Weir not stuck? No chance of obstruction in the suction line from the skimmer to the pump?

    Like I said, not my comfort zone, but I wanted to give this post a kick in the shorts to see if we can get more eyes on it. Let's see if we can get you some answers.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: New Motor and Pump Not Fully Priming

    10-15 psi is fairly normal for many systems. What do you mean "it doesn't fully prime"? Is there air in the pump basket? Sloshing or just a bubble at the top? How much flow are you getting out at the return(s) in the pool?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: New Motor and Pump Not Fully Priming

    Quote Originally Posted by Texas Splash View Post
    Not my area of expertise, but I wanted to give this a and ask a couple questions to help get this going for you. The psi comparisons you are referencing, that's from your filter housing correct? If so, I would be careful to judge pump/motor performance solely from that since we know the psi is also tied-into the resistance from the filter media as well. Some people have the same or lower psi readings when their pump is on high or low. My 2HP never goes over 10 psi even when I switch to high ... unless the filter is packed with gunk. So if you were to ignore psi for a moment, how is the water circulation? Is the return jet pressure similar to what you had before the original motor failed?
    - The new pump (wet end) you got from your friend, any chance the diffuser or impeller appear to be damaged or warped? Everything present (seals, impeller ring, etc) as noted HERE? I believe that's the same pump right?
    - Normally we would relate loss of prime to anything from the poolside skimmer to the pump wet-end, to include drain plug and possibly seal plate. But you already stated no water leaks when turned-off. Pool water level good? Weir not stuck? No chance of obstruction in the suction line from the skimmer to the pump?

    Like I said, not my comfort zone, but I wanted to give this post a kick in the shorts to see if we can get more eyes on it. Let's see if we can get you some answers.
    - The Wet end you noted with the link is the correct one.
    - Also after I hooked us the 2853 the water circulation was weak and struggled. When I mounted the 2858 to the wet end I had about the same circulation as I did with the old motor that died.
    - Also the diffuser or impeller don't appear to be warped of cracked in any way.
    - Pool water is a little over half way wanted to make sure the new motor didn't need more water.
    - I do not have a Weir (I had to look that up).
    - A obstruction in the suction line I would think there wouldn't be since the 1.5 HP motor was able to move more water.

    The weird thing is the outlets in the pool are not outputting any bubbles. I had this issue when I first moved into the home and it was because the plumbing was bad.

    - - - Updated - - -

    Quote Originally Posted by duraleigh View Post
    10-15 psi is fairly normal for many systems. What do you mean "it doesn't fully prime"? Is there air in the pump basket? Sloshing or just a bubble at the top? How much flow are you getting out at the return(s) in the pool?
    - When I say it doesn't fully prime I mean there is about an inch to inch and a half of air in the wetend skimmer. Looks like a continues slosh.
    - The return valves in the pool are getting great flow. Not sure how to measure that never have had too.

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    Re: New Motor and Pump Not Fully Priming

    - When I say it doesn't fully prime I mean there is about an inch to inch and a half of air in the wetend skimmer. Looks like a continues slosh.
    - The return valves in the pool are getting great flow. Not sure how to measure that never have had too.
    From that description, it sounds like you are suicking air into the system.

    Do you have to bleed off air from the filter time to time?

    Do the returns blow out any bubbles......maybe pretty continuously?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: New Motor and Pump Not Fully Priming

    Quote Originally Posted by duraleigh View Post
    From that description, it sounds like you are suicking air into the system.

    Do you have to bleed off air from the filter time to time?

    Do the returns blow out any bubbles......maybe pretty continuously?
    - I have not had to bleed air from the system yet.
    - The return jets do not blow bubbles that I am able to see. For example when I turn the pump on it will blow a couple of bubbles but after about 10 seconds it clear up and there there are no more that are popping on the surface.

    About sucking air into the system where would it be sucking the air in? I have replaced the Lid seal, siliconed up all joints on the suction side of the pipes. I cant find any leaks and have even doused water over all the joints and cant find any leaks. Also when I turn off the pump it doesnt back wash or lose any pressure at all. It holds all the water with no loss at all. I have turned off the pump and let it sit for a day and no pressure lost at all. I have even turned off the pump let it sit for a day and then taken off the lid to the weside of the pump then air began to rush in and I lost all the prime that I did have. Then I refilled the wet end of the pump put the lid back on and turned it back on and it was right back up and running.

    Would it matter that im running a 1hp Impeller on a 1.5 hp motor. Even though I was running a 1hp motor with the 1hp impeller and getting the same results this is when I upgraded to the 1.5hp motor to see if that would fix the issue.

    Only thing I have not done is replace the seal that goes into the front of the wet end of the pump.

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    Re: New Motor and Pump Not Fully Priming

    Quote Originally Posted by jmayhallfb23 View Post
    Would it matter that im running a 1hp Impeller on a 1.5 hp motor. Even though I was running a 1hp motor with the 1hp impeller and getting the same results this is when I upgraded to the 1.5hp motor to see if that would fix the issue.
    No that would not make any difference at all. Unfortunately, the pool store steered you in the wrong direction, what a surprise. If the motor you had was too small, it would shut off due to thermal overload so you know right away if it is too small. So I would take back the new motor and tell them it changed nothing and that you had the correct motor in the first place so you can get your money back.

    Also, a change in the PSI was not due to the motor, it was probably due to something else. When you say the impeller is clean, did you look inside each of the vanes or are you talking just about the inlet?
    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

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    Re: New Motor and Pump Not Fully Priming

    Quote Originally Posted by mas985 View Post
    No that would not make any difference at all. Unfortunately, the pool store steered you in the wrong direction, what a surprise. If the motor you had was too small, it would shut off due to thermal overload so you know right away if it is too small. So I would take back the new motor and tell them it changed nothing and that you had the correct motor in the first place so you can get your money back.

    Also, a change in the PSI was not due to the motor, it was probably due to something else. When you say the impeller is clean, did you look inside each of the vanes or are you talking just about the inlet?
    I checked the Inlet and the vanes. Both were spotless.

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    mas985's Avatar
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    Re: New Motor and Pump Not Fully Priming

    With the pump running, look inside the skimmer and see if it is creating a vortex which could suck in air.
    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

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    Re: New Motor and Pump Not Fully Priming

    The skimmer in the pool never creates a vortex and the Skimmer on the wetend of the pump also never creates a vortex. It just looks like it is coming in with no issues. When looking at the wetend skimmer of the pump the inlet is below the water level and stopping or running the pump it is never below it.

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    Re: New Motor and Pump Not Fully Priming

    - When I say it doesn't fully prime I mean there is about an inch to inch and a half of air in the wetend skimmer. Looks like a continues slosh.
    So the only thing that is an issue now, is there is a bubble of air about 1.5" in diameter at the top of the pump basket? If so, I would just ignore it. The flow rate may not be high enough to clear that out completely.
    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

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    Re: New Motor and Pump Not Fully Priming

    I will send a picture of what it looks like when i get home but its not a bubble. When i said 1.5 inches I mean its 1.5 inches of space between the water in the skimmer basket and the top of the lid. As if there is a major leak but It doesn't show the symptoms of a the leak or I cant find it. Any other way to test a suction leak?

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    Re: New Motor and Pump Not Fully Priming

    If it was indeed a leak, the filter would fill with air and you would see air out of the returns. If those two things are not happening, there is no air leak.

    Now there could be a small blockage in the suction line that is lowering flow rates enough so the air pocket does not purge but you said earlier, that you were getting strong flow out of the returns so that kind of rules out that as 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

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    Re: New Motor and Pump Not Fully Priming

    All Right.... Awesome News. I trouble shot the pump wetend (Hayward SP3200) all day and couldn't get it to seal and work. So I gave up and Installed the old wetend pump (Pentair) which I have heard that are old but very dependable. As soon as I hooked it up with the AO Smith 2853 it primed and started pumping away.


    Now I have another problem.
    My pump either burned out or is over heated. It turned itself off and it was crazy hot. So after a little research I learned that the impeller on the Pentair was a 1.5 HP and the old motor was 1.65 THP and the 2853 is 1.25THP so I thought that was it. Next step I took was I tore down the pump and installed the AO Smith 2858 and installed it and turned it on and was rocking like a champ.

    Now where Im worried is this is a brad new motor and its HP=1.5 and the SF=1.5 so the THP=2.25. When I let the pump run for about 30 minutes while I was cleaning up my mess of everything I went over to check my work and be proud. I smelt the same smell that I was smelling with the other pump before it turned itself off so I felt the pump and it was rather hot to the touch like the other before I turned it off. So I turned off the pump and here I am.

    Any advice. Im worried I may burn up or hurt my new pump.

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    Re: New Motor and Pump Not Fully Priming

    Good News,

    After research I was confided that the new motor would die on me and if it did I would just take it back since the impeller was 1.5hp I turned on the AO Smith 2858 and haven't had a problem yet.

    Thank you all for all the help and information.

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