Pump Not Priming Mystery

[Seadweller]

I'm trying to help my neighbor get his pool back up and running after the hurricanes here in the Tampa Bay area. He was having issues with the original pump, as it would not prime/flow properly. He always had a half-full volute, regardless of the valve settings. He just installed a new pump, and it won't prime at all. I've removed all the valves, run a hose through the plumbing, etc., so there's no blockage that I can find. I ran pressurized water through the skimmer port, and it came flowing out of the pipe, but I can't get the pump to prime. I've ruled out any issue beyond the pump.

I've poured a number of 5 gallon buckets into the pump, put a hose in the simmer port to assist, etc. to no avail. I'm completely stumped.

Anything else I should be checking?

 

[Texas Splash]

Any chance you could post some pics of your neighbor's set-up? Pool, pad etc from different angles. That could help a lot.

 

[PoolStored]

Did you ensure there were o-rings on the pump lid and drain plugs? Did you lubricate them with silicone lubricant (not PTFE/Teflon lube)?

Turn off the breaker to the pump. Ensure that the pump has no power. Put your hand in the pump and ensure the impeller is present and attached to the motor shaft.

 

[Seadweller]

Below are some pictures....Brand new pump, and everything is as it should be....I tried priming the pump through the drain to eliminate anything further downstream, and nothing.

 

[Texas Splash]

I would first close the drain line. The spa is already closed, so adjust the 3-way valve to pull water only from the skimmer. It's easier on the pump. Fill that skimmer suction line first. Once the pump can achieve full prime from the skimmer, then "slowly" open the drain and see how that goes.

 

[Seadweller]

Thanks…I tried that, and every combination you can think of as well. If you look closely, the main drain line was cut and capped off, because the main drain was evidently leaking. Some pool company filled the main drain with concrete.

That’s why I’m so mystified, I cannot draw a prime from any of the lines, altogether, or individually.

 

[Texas Splash]

If you look closely, the main drain line was cut and capped off,

Geez, I looked right at that thing. I'll blame that on being a Monday.

Okay, so the two scenarios (old pump half full and new pump no prime at all) certainly could be related - either plumbing or a valve. It doesn't take much. You mentioned you removed all valves for access to push water and check for a blockage. Naturally that doesn't rule-out the possibility of a broken pipe, but as PS noted above, did you notice anything odd with any of the valve seals? Did you apply fresh pool lube?

If it were me, I'd be very suspicious of that actuator valve. Regardless of manual 3-way valve configuration, if there is a problem in that actuator valve , you can't pull water from either side. Since your neighbor struggled with air with the old pump, and that actuator is the first thing before the pump(s), I would really check that closely. Sometimes they jam-up internally and you won't know it. Also be very critical of any seals. Try lubing all the internal seals, and to be safe, try manually engaging that actuator valve to ensure it's opening completely. It may need to be replaced.

If that doesn't work, also be sure that the weir door/flap isn't closing or getting stuck interfering with water flow into the skimmer.

Last but not least, something I did in the past when I struggled with prime was do a test with some spare PVC. I made a single (temp) suction line from the pump straight into the water like a big straw. I did that to eliminate the underground lines and any valves just to ensure the pump was fine. Last resort perhaps.

 

[Seadweller]

Thanks...I've essentially ruled out most everything that you mentioned, except for the one automated actuator valve which is the only one I did not take apart, so I guess that's the next step. You would think that even with a minor air leak, the pump would prime but be full of bubbles/air. I'm not getting a drop of water coming into the volute.

 

[Texas Splash]

You would think that even with a minor air leak, the pump would prime

Yeah, I hear you. That's why I'm also questioning whether the valve is actually opening inside completely to allow full, unimpeded water flow. Perhaps both issues?

 

[Seadweller]

I'll pull that valve today. It's the last thing in the way of the water flow to the pump. That will completely rule out an equipment issue, other than the plumbing from the pool itself.

 

[Seadweller]

Well, pulled the valve, found no blockage and the flapper is operating properly and in the correct position. Essentially, all 3 valves are working properly so I can rule those out completely now. I've run pressurized water into both the skimmer port and cleaner port, and water is flowing through the pipes. The 3rd return is from the main drain in the SPA. I still can't get the pump to prime through any one, or combination of returns. To say I'm baffled is an understatement.

 

[Texas Splash]

Maybe one of those things we're over-thinking. Once an air leak and/or plumbing restriction is ruled out, water should flow. Is that equipment pad at the same height as the pool water level, or that equipment room below water level by chance?

 

[Seadweller]

Maybe one of those things we're over-thinking. Once an air leak and/or plumbing restriction is ruled out, water should flow. Is that equipment pad at the same height as the pool water level, or that equipment room below water level by chance?

The pool pump is actually above the water level in the pool on a raised pad. The pump inlet is probably 18"-20" above the water level in the pool.

 

[Texas Splash]

The pool pump is actually above the water level in the pool on a raised pad. The pump inlet is probably 18"-20" above the water level in the pool.

Okay, so that could definitely make it a bit more difficult for water to eventually make it to the pump. In your first post you noted trying 5 buckets of water in the pump pot already. As an example, sometimes when I empty my pump pot, I have to fill and refill it some 5-6 times just to eventually get the suction line to fill all the way from the pool to the pump and my pad is level with the water. I have to remove the lid rather quickly, fill it, replace lid, and start it up again that many times. As soon as the pot water is pulled out, I stop and refill. It doesn't always happen, just an odd thing for me. Perhaps your neighbor's suction line is simply struggling the same way, but even more so with the pump a bit higher than the water. It may need several more attempts until that suction line is completely full. As soon as the pot empties, fill it again and repeat.

If everything is ruled out, I can only think of that temp suction line test.

 

[Texas Splash]

This is what I ended-up trying when I questioned a possible leak.

Suction Leak - Do You Have One? Try a Big Straw!

DISCLAIMER: Safety First! Our pool is still CLOSED. The water is too cold so there are no swimmers, no risk to life or limb due to exposed suction pipe in the water. This was my own personal test conducted in a fenced/controlled environment for less than a 24 hr period. This was a...

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