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Thread: Pump Help - Not priming

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    Pump Help - Not priming

    Boy...finding how to post a new thread is challenging. Anyway....

    Folks,
    Pump is turning but will not prime. Iíve taken to removing the strainer basket and holding my hand over the inlet port at the bottom of the basketÖ..nothing. Also with basket and lid in place Iíve checked for vacuum at the D.E. filter bleed screw, usually that will start with a vacuum and then turn to pressure when the filter fills, again very little to nil vacuum. I canít pull the pump till next week, but does it sound like the impeller has gone? All was ok until I turned the pump off and threw the two valve flow directors from pool to spa, then masses of churning in the basket but no pressure in the filter. Moving them back to pool has not fixed the problem. I have moved them back and forth with the pump off each time, but no pressure or water draw from the pump. Thoughts, suggestions welcomed.
    Thanks

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    JasonLion's Avatar
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    Re: Pump Help - Not priming

    Is the pump making any noise at all, especially an unusual noise, when turned on?

    Frothing in the pump strainer basket usually results from a suction side air leak. The first place to check is the seal on the pump strainer basket lid. The seal should be clean and free of any nicks or cuts as should the surface it seals against. Many other locations are candidates for where air could be coming from, though that is the most common.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    epro05's Avatar
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    Re: Pump Help - Not priming

    When I re-prime, I remove the basket lid, then pour water into the basket using a water hose, quickly replace the basket lid and turn on the pump, and open the filter bleed screw. Not sure if you are pouring water into the basket but for me it helps with the re-prime.
    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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    Re: Pump Help - Not priming

    Thanks guys. I don't think it is a gasket or hose prime issue. I have tried those. It was working fine until I stopped the pump and threw the two Jandy valves to 'spa', and then it churned away. At the moment I am perplexed. The impeller seems to be attached to the motor shaft, I can turn the motor shaft and feel the impeller turning. As I recall it's a left hand thread screw onto the shaft so I don't think it would slip as it is screwed on. It may be blocked with some debris, I'll have to wait till weekend and pull pump apart. I've tried eliminating possible inbound issues with the pipes by way of setting the Jandy valve to either all spa or all pool. Also the Jandy that allows skimmer or main drain inputs, I've also set that full one way or the other, no joy. I've stripped the Jandy's and cleaned them but will get new o rings in case it is that. When you drop the power to teh pump you can hear water draining from around the filter / pump area. Obviously that should not be happening. I can't see any cracks in the pump primer reservoir or in the flange that mounts to the motor, with that said it looked wet around that area this morning before I had the problem, so maybe there is a leak somewhere in the motor internals or....could the DE filter have a leak and cause this type of problem? It's all very peculiar. When I feed a running hose with the pump motor running it seems to swallow that fine, so it sounds like the impeller is working. Could a leaky pump seal cause the problem?

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    JasonLion's Avatar
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    Re: Pump Help - Not priming

    Having the plumbing drain down when the pump is off means there is certainly a leak somewhere. The leak is almost certainly either on the skimmer/intake side of the pump or in the pump it's self. Switching the input between pool and spa not having any effect does narrow things down a great deal, but still leaves at least a little pipe and a connection or three that could be involved.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Pump Help - Not priming

    I'll pull pump at weekend. Over the last 13 years the only time I've ever had prime issues was a very slight loss when the strainer basket gasket dried and just a smear of PTFE cured that. Is there a possibility that the seal surfaces may be slipping? So...the shaft turns normal speed, the impeller turns, but there is slippage under torque on the seal, so it results in churning? Also, crazy question....could the motor malfunction in such a a way as to turn in the opposite direction? I can't see how that could happen. Finally....the DE filter....can any vacuum problem there cause a loss of suction, or is the problem upstream of the filter for sure? I know when you open the bleed screw atop of the filter you get suction for a few seconds until the filter starts to fill with water, then the suction turns to pressure. I'm not getting any suction at all at the bleed screw. I did read about covering the pipe / valve joints with shaving cream and looking for dimpling that would indicate a vacuum leak, anyone had success with that? I did think if there was a way of jamming a hose into the basket pump inlet and then drop the hose into a dustbin full of water and see if it will prime?

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    Re: Pump Help - Not priming

    Pulling the pump is your call but my bet is the pump has nothing to do with your air leak.

    There are many, many things to check but the leak will be found somewhere between the pump strainer basket and your skimmers....not after the pump.

    If the issue started when you switched the "two valve flow directors", start there. Do those valves change the source of the intake from pool to spa?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pump Help - Not priming

    Quote Originally Posted by duraleigh View Post
    Pulling the pump is your call but my bet is the pump has nothing to do with your air leak.

    There are many, many things to check but the leak will be found somewhere between the pump strainer basket and your skimmers....not after the pump.

    If the issue started when you switched the "two valve flow directors", start there. Do those valves change the source of the intake from pool to spa?
    yes, I have 3 jandy's.

    1. This Jandy Controls the amount of water pulled from skimmer or main drain. (Not touched as part of the original problem)

    2. Upstream from Jandy 1 is another Jandy that controls Pool or Spa. The output of this Jandy feeds into the strainer basket. This was moved from Pool to Spa prior to the problem.

    3. Jandy that is after the filter / heater and controls the amount of flow back to the pool / spa. This was moved from Pool to Spa prior to the problem.

    I've tried moving the Jandy's in the hope of pulling water from either the pool or spa only, trying to see if that would eliminate the problem. Not water flows into the strainer basket regardless of Jandy positions.

    The day before I stripped and cleaned the filter grids. Like a lummox, I managed to tread on the steel ring between the filter halves and distort it. I got it back to shape (sorta) and fitted the rubber gasket and tank top back together, she fired up like a champ, no problems and ran at normal clean filter pressure. Don't know if that could be involved in problem, but I cannot see any water leaks from filter.

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    Re: Pump Help - Not priming

    Further thoughts, comments welcomed. If I can jam a tennis ball into the pump basket intake port, similar to how you would do if blocking a skimmer input port, then....that pump should suck like crazy and hold that tennis ball fast. If it does not, then the leak is somewhere in the pump area and not in any line from the pool. Thoughts?

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    Re: Pump Help - Not priming

    Have you read the article in Pool School on suction side air leaks? These leaks ONLY occur from the pump impeller to the skimmers.....the suction side of your system
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pump Help - Not priming

    Thanks let me take a look at that. I was also seeing on an INYO pool video, references to gaskets in the strainer / diffuser / impeller area, so I'll look into that. Obviously I'm hoping it isn't any piping damage underground. I'm assuming that if I can throw the Jandy to either completely pool or completely spa inputs then I would be using a separate feed to the pump. Appreciate it thanks. The pump assy by the way is the Challenger / Pentair config, it has the steel band around the motor to plenum connection.

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    Pac - Fab / Pentair Loss of Pump Prime

    The problem turned out to be a broken diffuser. For the novice, (like me) in the pics attached you see the diffuser in two parts. It's supposed to be one assembly. The small component had clean broken off the main assembly. Inside the small component you can see a rough copper / blue material. That is what is left of a brass or brass composite bushing that starts life about 1/8 inch thick and is pressed into the diffuser. The impeller rides inside that brass bushing. The impeller was fine, no appreciable wear on the impeller part that mates up with the brass bushing inside the diffuser. For you folks that have this style of pump, they are very easy to dismantle. Basically, there is a metal band / clamp that holds the motor assembly to the pump housing. Undoing the clamp and removing the metal band will allow you to pull the motor assembly out. With the benefit of hindsight, I should have pulled the motor assy first, as I said they are super easy to pull. What happened was, the problem started after I threw the Jandy flow directors from Pool to Spa. That sent me off down the road of dismantling Jandy's and checking O rings. Fortunately I have not introduced any other similar problems.....but I could have done. It was just the straw that broke the diffusers back, that how sod's law works doesn't it?
    Also....You Tube has some good vids on there for chasing down prime problems. Everything from a hose being dribbled over joints to a guy with incense sticks watching for smoke being drawn into piping joints. I think he was either from Denver or Washington, or maybe Amsterdam, not sure. All good fun. Good luck and thanks for the help.

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    epro05's Avatar
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    Re: Pac - Fab / Pentair Loss of Pump Prime

    Same thing happened to me last month. I wasn't having a prime problem though. My motor had been overheating all summer and tripping the thermal protector after about an hour of running, but I could never figure out why. I lived with the overheating until December, then the motor completely died. When I was replacing the motor, that's when I found my diffuser was broken. I'm wondering if the broken diffuser was causing the overheating, eventually killing my motor.

    The other thing I found is that my pump and impeller was sized for a 2 hp motor, but my motor was actually 1.5 hp. A while back I had my motor replaced by a pool guy, and I suspect he took out a 2 hp motor and installed a 1.5 hp motor. So when I recently ordered a replacement diffuser (and impeller), I got the correct ones to match up with my 1.5 hp motor. This could be another reason why my motor was over heating, but it didn't overheat for about 10 years, so maybe the broken diffuser was somehow putting extra stress on the motor. Not sure.

    Just so you don't feel alone, here's my broken diffuser. Looks similar to yours. I wonder if this is a common problem.

    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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