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Thread: baffled: suction leak or not?

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    iam4iam's Avatar
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    baffled: suction leak or not?

    My pump has always had a slight suction leak at the pump basket lid, as evidenced by bubbles in the pump basket (until the pump primes), squirts from the basket lid when the pump shuts off, and water loss in the pump basket when the pump is not running. The leak has not been bad enough to prevent the pump from priming, provided the pipes are relatively full. However, I occasionally have to take the basket lid off and use a hose to add water to fill the basket. The real problem is that the lid is not the original lid and doesn't fit exactly right, but apparently well enough to create a close to airtight seal on the gasket. The pump is so old that all I can tell what model it is, which is why I never replaced the lid. I've tried various things to seal the lid, but this week, when I finally thought I had it sealed for sure, suddenly the pump stopped moving any water at all. I thought the impeller might have been obstructed, but I confirmed that was not the case by removing the back cover and spinning it manually with a screwdriver. After another adjustment on the basket lid, the pump started to move water again, but only very slowly. The pump basket doesn't fill and I still see bubbles in the pump basket as the water passes through, which would indicate that there is still a suction leak. However, when the pump is turned off, water doesn't spit anymore and the water level doesn't go down, which would seem to indicate that there isn't a suction leak.

    I've looked at numerous threads on failure to prime and haven't seen explanations other than suction side air leak or impellor obstruction. Can the pump just become weak over time, or do they just suddenly stop working altogether? I'm prepared to replace the pump with I can actually read the label on, but I'd obviously prefer to save that money (or spend it on something else)! Any ideas?

    Water temperature is nearing 60 degrees, so I need to do something soon. Thanks to TFP, I've been crystal clear since I finally beat the green two years ago when opening the pool for the first time since we bought the house.

    Edit: Not that this could be a factor, but the (current) priming trouble started after replacing my SWG. (I removed it for the winter and created a new section of PVC to replace where the SWG goes using unions.) I don't see any leaks on the pressure side at all, though. Also, a friend of mine told me using backwash mode on the filter seems to help fill the lines and remove air from the system, so I tried that, but it didn't help. Right now the pump is putting about 8 PSI on the filter. Normal is 16-20 PSI. Can problems on the pressure side cause failure to fully prime?
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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    Patrick_B's Avatar
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    Re: baffled: suction leak or not?

    Just curious, but why not try and obtain the correct lid?

    This is a really important piece of the pump assembly.
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    Re: baffled: suction leak or not?

    Keep in mind that if you have air in your system (and you do), you have a suction side leak....period.

    Air leaks do not occur on the pressure side.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    iam4iam's Avatar
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    Re: baffled: suction leak or not?

    I haven't replaced the lid because the pump is so old that I can't tell what model it is. (I can't blame Patrick for not noticing that explanation hidden in my "dissertation" of a post!)

    Is it possible that the bubbles I see in the pump basket are not due to air but just due to water sloshing in the bucket and that the pump just simply no longer has enough power to suck in enough water to fully prime? Or do pumps just suddenly "give out" without "weakening" first?
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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    Re: baffled: suction leak or not?

    Is it possible that the bubbles I see in the pump basket are not due to air but just due to water sloshing in the bucket and that the pump just simply no longer has enough power to suck in enough water to fully prime?
    Then you would have virtually no flow at the returns.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    iam4iam's Avatar
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    Re: baffled: suction leak or not?

    Quote Originally Posted by duraleigh View Post
    Then you would have virtually no flow at the returns.
    Which is not the case. Return flow is decent (with plenty of air).

    Plus, I was wrong about the water level in the pump basket. It did drop in 24 hours. Looks like I have to concede that there is a suction side leak and find it. I wish I had some way to determine what lid is compatible with this old pump. What I've read in a couple of threads* about pump life makes me think the pump I currently have may may have more life left in it than than many new pumps I could buy to replace it, and I don't even know how old it is!

    *life expectancy of pumps and need new pump
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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    Re: baffled: suction leak or not?

    Pump running, allow water from a spigot to flow over the pump lid.

    If that is the source of your air leak, it should minimize or stop. You will know for sure that's the source, at least.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: baffled: suction leak or not?

    Quote Originally Posted by duraleigh View Post
    Keep in mind that if you have air in your system (and you do), you have a suction side leak....period.
    period......or a blockage in the suction line(s). Probably not relevant in this case but I recently had a sock (don't ask how) trapped just before the suction line entered the pump basket! Pump basket full of air and zero flow from the return lines. Really happy to find the sock as the first step of trouble shooting thanks to the good folks here sharing info.

    Brian
    15,000 ig plaster (kidney shape approx 30'x16'), Hayward 1.5hp "Max-flo" pump, Hayward DE filter(48 sq. ft effective filtration area, 96gpm, 6lbs DE), TF-100 Santa Barbara, CA

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    Re: baffled: suction leak or not?

    period......or a blockage in the suction line(s).
    and still a suction side air leak. Splitting fine hairs here.

    However your sock got in there, it caused a low enough pressure on the suction side to temporarily break one of the seals and allowed suction side air to be pulled into the system. That broke prime which was why you had no flow.

    It is important to realize that an air leak comes from the suction side of the system and DOES NOT come from the pressure side. It is very helpful in finding the leak.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: baffled: suction leak or not?

    Well, I used some silicone to make sure the lid was airtight (or at least so it appears*), and managed to get enough water flow for the SWG to function. However, filter pressure stopped climbing at about 11 PSI, which is still 8-10 PSI short of what I would expect, so water flow is clearly still not normal. Clean filter pressure (before adding DE) is 14 PSI, and I haven't backwashed since early June last summer. Another (possibly related) quandary is why my SWG only raised FC a fraction of what is should have since it turned on. Fortunatley the water is still below 60 degrees (barely). FC was only 1-1.5 ppm last night just as the SWG turned on. 6 hours running at 100% should raise my FC about 4 ppm, but it was only 3 ppm (+1.5) when I checked this morning. Ran it another 6 hours this evening and it's only at 4 ppm now. CC < 0.5, in case you're wondering, and water is crystal clear. Is the amount of chlorine gas the SWG produces a function of how much water passes through it? (This could be a pertinent question in deciding whether to buy a 2-speed pump!)

    *Pump basket is nearly full of water when shutting off pump, and there is no squirt of water from around the lid when I turn off the pump, but I guess air can fit through a smaller space than water, so that doesn't necessarily mean the the lid is airtight. (I still see a few bubbles, but not many. I just hope I don't have an air leak underground!)
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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    iam4iam's Avatar
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    Re: baffled: suction leak or not?

    A little more reading on TFP answered my question about water flow affecting SWG chloring production. Thanks TFP!!! Not sure why mine is producing less than half (around 1/3) as much as it did last summer, though. I can't afford to be running the pump 3 times as much as last summer! Need to perform further investigation. I'll do some more reading on this site in the SWG section.

    As for suction leak, I made out a very faint "WA" insignia on the pump, and figured out it stands for "Water Ace," and I ordered what seems to be the replacement lid. Hopefully that will make a difference.
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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    iam4iam's Avatar
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    Re: baffled: suction leak or not?

    New lid fits perfectly and no more air leak! Pump still takes awhile to completely purge air from the system, but once the pump basket is full of water with no air bubble at the top, it stays that way!

    TFP rocks!
    ~18,000 gal (16x32)
    Hayward sand filter
    Circupool RJ45 SWG
    Hayward Max-Flo XL SP2305X7 pump (0.75 HP)

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