A mystery to me: Why can't I get prime?

brad2167

Member
Apr 24, 2021
13
Raleigh, NC
Hello All,

Please forgive the long message. Been trying to figure out what to do next and thought making a history log would be my best way to retrace my steps and decide what to do next.

Approx 3 weeks ago, after a heavy rain, my pump failed to keep prime. Previously had kept and restored prime for approx 3 months. In prior year, we did vacuum too much debris into the line and lost prime. Cleared it and restored prime this spring. Had run it 24/hrs a day without issue.

After this storm, the symptom was that the pump housing would not fill, instead leaving me with 50/50 air water. Good water levels in the pool, as water was at approx 3/4 height of the skimmer. There is no drain in the pool, so this skimmer is only exit from the pool.

I have done the following, in roughly this order:

1) First debug was to replace the pressure gauge. No change in behavior.
2) Replaced pump housing gasket and re-lubed. No change.
3) Replaced sand in the Hayward sand filter. Was due anyway, but no change in priming.
4) Replaced Hayward 1HP SuperPump with a new Hayward 1.65 HP SuperPump.
5) Successfully blew water from pump to skimmer using wet/dry vac. 1.5" PVC flex pipe.
6) Successfully blew water from skimmer to pump using wet/dry vac.
7) Able to snake approx 17 ft from pump side towards the skimmer - then hard stop.
8) Able to snake <2ft from skimmer towards pump - then hard stop.
9) Re-lubed the new pump's housing gasket.

I see/feel/detect no airleak on the suction side. I am confused by the fact that the line passes water both ways, but can not be snaked by a simple toilet snake.

When I prime the pump, it runs at high speed for 8 minutes, and then drops down to a lower speed. Even if I raise the minimum speed to the pump max (3450 rpm), I see no difference in the rate of water coming into the pump, although I do get more flow back into the pool.

The skimmer is submerged into the ground, and plumbing connections are not accessible. Below ground and behind a wood frame used by the decking. Getting to that plumbing for examination (why can't I snake it?) would be a labor intensive pain in my Rear.

I have tried to include photos as well for reference.

I have had 3 different pool companies look at this situation over time (last fall, spring, and 2 weeks ago). None of them could diagnose a reason, but at least the first two cleared the line and got me back to prime. The third one looked at my prior pump and said he did not want to take it apart so he would not work on the issue. I have called two more and they do not have the manpower for a service call.

So, what would you do next? Any help or suggestions are appreciated.


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Brad,

You have an above ground pool. Unlike inground pools where you have to suck water out of the pool, gravity should force your pool water to just flow right into your pump.

I assume the equipment is below the water level in your skimmer.

If you take the pump lid off, water should just flow right out. To me this means the problem is that the pump has no place for the water to go. Meaning that something in the path between the pump's output and return to the pool is blocked.

I'd disconnect the union between the pump and the filter and see if water comes out of there like a fire hose.

I assume you have checked to make sure the impeller is not plugged or broken off the motor shaft.

Thanks,

Jim R.
 
Hi Jim R,

Thanks for your response. As the pool was originally constructed (10-12 years ago), the pump was approx. 1 foot above the pool water line. The pump was able to draw and maintain prime during that time. I have owned the system for 2+ years now and it has certainly been finicky, but I have had long periods of prime. I am going to fill the pool to the top of the skimmer tonight again though.

I agree having the pump below the pool line would be better, and maybe even as intended, but that is a major inviestment I can not make at the moment.

Similar to your suggestion - When I diconnected from the pump and pushed water using my wet/dry vac - water did flow out of the pipe. Definitely not a fire hose though as it was driving uphill slightly.

I have checked the impeller of the old pump and the new pump before and after I installed it. Always turned freely.

Thanks,
Brad
 
Hey Jim,

I replaced the entire pump and pump housing. A full new unit from Amazon for the Hayward W3SP2603VSP Super Pump VS Variable-Speed Pool Pump, 1.65 HP. This was the recommended replacement/upgrade for the very old Single Speed 1 HP Hayward Superpump. The amazon product description includes this: "Designed for small to medium in-ground pools and spas...."

I have never been able to tell if the pump was intended for the inground or above ground market. At the time of this pool install, the pool company referred to the pool as a hybrid, which just feels like a sunken inground pool to me. There is no poured concrete and it had a liner.

Looking at other systems pictures, I have seen these pumps in poolhouses for inground pools, but I have no direct evidence one way or the other.

Thanks for spending your time on me,
Brad
 
Brad,

An inground pump should work just fine on an above ground pool. An above ground pump will not work on an inground pool.

In ground pumps work off of suction, so if the line going to the pool has an air leak, the pump will never be able to draw a vacuum.

If you were running your original pump 24/7, then it only had to prime if you actually shut the pump off.

I like Dave's idea, try that and see what you find.

If you have a by-pass or recirculate option on your filter, try that and see if it makes any difference,

Thanks,

Jim R.
 
Turn on the pump and open the pressure relief valve on the filter. Even if it doesn't prime, you should feel air blowing out (not too much but some) let us know
My sand filter has a Control at the top, "Vari Flo Control Valve", and I have a drain cap at the bottom, but I see no pressure relief valve.

I did just empty the sightglass and retighten, then ran it through a backwash settings until clear, then a recirculate for a few minutes, and, and have placed it back into filtration.

Adding more water now to bring level up higher.

I do not see any change in behavior.

- Brad
 

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Brad,

I'm confused... Not too unusual for me.. :scratch:

How is it possible that you can backwash and rinse your filter, if the pump is not work???

When you backwash, does the blue hose fill with water?

Thanks,

Jim R.
 

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Brad,

I'm confused... Not too unusual for me.. :scratch:

How is it possible that you can backwash and rinse your filter, if the pump is not work???

When you backwash, does the blue hose fill with water?

Thanks,

Jim R.
I appreciate the continued questions and the whole reason I posted today is that I am confused.

Everything operates, but it operates poorly and slowly.

In filter mode, I get a lot of air in the basket and my return has a lot of bubbles, but water is flowing.

In backwash mode, the blue hose pulses a little and has a weak flow but backwashes - the water in the sight glass is dirty and then clears in a few minutes. When I had a primed system, the blue hose filled. during backwash.

So - if I had a way to bleed the air out, it might work better.

I am almost convinced that the flow from the pool through the skimmer is impeded in some way and I am going to have to dig the thing up again.

- Brad
 
I am almost convinced that the flow from the pool through the skimmer is impeded in some way

Brad,

Well, flex line can collapse... This means that when you used your wet vac to push water through the flex line it could open up, but when the pump is sucking on the flex line, it could suck it partially closed.

Thanks,

Jim R.
 
Brad,

If this were my pool, I would not want to cut up the deck unless I knew for sure where the problem was. I suggest that you run a temporary line from the pool to the pump. I guess it would depend on how much work it would be to run a temporary line vs, cutting up the deck.

If you run a temp line from the front of the pump to the pool and it still did not work, you would know that it is not a skimmer line issue. If it did work, then you'd know for sure the issue was with the skimmer line.

I'd just hang a pipe over the edge of the pool and into the water. Keep in mind this would just be for running some tests.

Thanks,

Jim R.
 
Brad,

If this were my pool, I would not want to cut up the deck unless I knew for sure where the problem was. I suggest that you run a temporary line from the pool to the pump. I guess it would depend on how much work it would be to run a temporary line vs, cutting up the deck.

If you run a temp line from the front of the pump to the pool and it still did not work, you would know that it is not a skimmer line issue. If it did work, then you'd know for sure the issue was with the skimmer line.

I'd just hang a pipe over the edge of the pool and into the water. Keep in mind this would just be for running some tests.

Thanks,

Jim R.
Interesting idea. So a straight shot from pump to pool, entering the pool through a sweeping elbow to get the most gradual slope up to the pump.

Trip to hardware store tomorrow for some pvc pieces seems to be in order. - Brad
 
On other news, raising the water level to top of the skimmer and running the pool overnight seems to show less air in the pump housing, but still bubbles out to the pool.

So I am gonna keep running it till I can try the test suggested by Jim R. If the problem is an intermittant pinch, maybe this will work it to a steady state.

- Brad
 
Hey gang. Finally have results from the test suggested by @Jimrahbe !

Photos attached, but connected a 20 ft PVC tupe from pool to the pump, which resulted in bypassing the skimmer and existing pipe.

We have completely successful prime and have enough flow to push water clear across the pool and enable the heat pump!

So, the pump location should be good to move forward, and the problem seems to be in the line from skimmer to the pump.

We will run the rest of this season on this jury-rigged pipe (after I attach some sort of mesh to the end to block , and see what sort of deck project develops in the next few months.

Thanks for all the help,
Brad
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