Pump Loses Prime: Could it be the shaft seal?

[garin33]

Hello Experts!
I have an infinity edge pump that started losing prime when left off over night. It started a few months ago. I have been trying to find the problem. There are no water leaks on the either side of the pump. The pump is only 1 1/2 years old, its a Whisperflo pump. I first thought it was a ball valve that was on the pressure side so we took out the ball valve and replumbed everything on the pressure side and it still leaked.
You could hear a very quiet sound of water running but it was too hard to detect where it was coming from even when you put your ear to the pipe. It seem to be traveling along the entire pipe. During that time of trying to figure out where it was coming from, it seem to get a lot worse after the pressure side was replumbed and the ball valve eliminated. So one time, the pump went completely dry and when the timer started it, it did not have a water to prime. So it ran dry for maybe 12 plus hours. When I noticed it, the water was super hot and steaming when I took off the pump lid. I reprimed the pump and everything seem to be ok. We noticed that if you sometimes wrapped your hand around the coupler on the suction side that the sound changed. So we thought there was probably an air leak where the coupler is glued and replumbed the piping on the suction side. However, it still loses prime in a couple of hours after replumbing the suction side. Now I hear a loud water sound when the pump is off and it seems to be coming from the pump itself. So I'm started to think that maybe at the beginning it was just a leak on the suction side fitting but because it ran dry, now there is also a leak on the pump at the shaft seal or faceplate seal? I asked my pool guy and he said that because there is no water leaking from the pump, he does not feel that replacing the shaft seal or faceplate seal will make a difference.
This pool issue is driving me crazy. I wanted to get your opinions on this. If the pump is leaking no water, could there still be a small air leak on the shaft seal or some other seal? Could this small air leak cause the pump to lose it's prime after the pump is turned off for a couple of hours?
I don't want to replace the shaft seal and other pump gaskets if that is a waste of time. Thank you for any input. I'm so frustrated with this and my pool guy also has no idea what it is. We have replumbed the suction side plumbing and the pressure side plumbing. I have replaced the basket lid and O ring lid. There is a check valve on the pressure side and I took it apart and inspected it and everything looks good. I put some lube on the cover and O ring to make sure it was snug and tight.
Thank you!!
Garin

 

[zea3]

Please post a photo of your equipment pad and plumbing, also a photo with the equipment pad and pool in the same shot if possible. By any chance is the pool at a lower elevation than the equipment pad?

 

[garin33]

Thank you. I will post some photos. Please note that I recently removed the ball valve you see on the pressure side. I will post updated photos tomorrow when I take some more pictures tonight.
Yes, the equipment pad is higher than pool and its much higher than the water level of infinity basin. Note: The infinity edge pump is only connected to the infinity basin, its completely isolated from the filter, heater, and the rest of the pool plumbing. I had the pool built 12 years ago and everything in regards to the infinity basin has worked fine. About 1 1/2 years ago, the motor burned out the infinity basin so I had them replace entire the pump. It worked great for 1 1/2 years and then suddenly started losing prime over night. When we replumbed the suction and pressure side we replaced the unions and used teflon tape on threads and checked connection. Thank you for your input.
Sorry, I don't have a photo of equipment pad and pool. Will try to take one later.

 

[zea3]

Check the drain plug on the pump pot and make sure it is hand tight. I also doubt the shaft seal is the problem since there is no water leaking at that point. The shaft seal is on the pressure side of the pump and squirts water when it doesn't seal correctly. If that is not the problem, you may want to try moving the check valve to the intake line for the pump. Where it is positioned now the water from the pump could drain back into the pool skimmer.

 

[garin33]

Thank you for your comment. I will check the drain plug on the pump pot. Thank you for the comment on the shaft seal. My pool guy felt the same as you. There is no water leaking anywhere, dry as a bone, so he felt the shaft seal is not an issue. The infinity pump only goes to the infinity basin and to the pool. It does not go to the skimmer. However, I guess the pump could drain back to the infinity basin? This is the same setup that I have had for 12 years and everything has been fine, so would that mean I don't need an extra check valve on the suction side? I don't have much room on the suction pipe to put anything else. Thank you.

 

[garin33]

I checked the drain plug and it was tight. I have never taken off drain plug since the pump was installed. Any other suggestions? Thank you.

 

[zea3]

Only other thing I can think of is checking the water level in the infinity basin. There shouldn’t be a vortex where it returns to the pump. If you see a tight swirl at that intake point it will draw in air. If that is occurring raise the water level.

 

[zea3]

What type of filter do you have?

 

[mknauss]

I checked the drain plug and it was tight. I have never taken off drain plug since the pump was installed. Any other suggestions? Thank you.

I would suggest you take the plugs out and check the orings. They can dry out and crack. Should be lubricated with Pool lube at least every year. You can get orings at a hardware store or Home Depot.
May not be the issue, but eliminating the possibility is worth it.

 

[garin33]

Thank you. The infinity basin has plenty of water and no vortex because there is a lot of water in the basin. The filter is a pentair. However, this pump is completely isolated from the rest of the pool system. It doesn't go through the filter. It goes from the pool to the pump, directly to the infinity basin. That is what is so frustrating, it should be rather simple to find and yet my pool guy and I are totally stumped. When you turn off the pump, you can definitely hear a loud hissing sound coming from the pump and water flowing through the pipes. But no water leaks at all when running or off. As mentioned, I had the pool built 14 years ago and have never had this problem until now. I have tried using soapy water to see if any of the bubbles are sucked in when I turn off the pump but I see nothing.

 

[garin33]

I would suggest you take the plugs out and check the orings. They can dry out and crack. Should be lubricated with Pool lube at least every year. You can get orings at a hardware store or Home Depot.
May not be the issue, but eliminating the possibility is worth it.

Thank you. I will take them out and inspect them. I'm desperate at this point, so I will try anything. My only thoughts now is there could possibly be a small underground air leak on the suction side?

 

[garin33]

One other comment: If the pump housing is making a loud hissing sound when I turn off the pump, does that mean there is an air leak somewhere in the pump? Seal plate gasket, shaft seal, etc. But note, no water leakage. Note2: I have already replaced the basket lid, o ring and magic lube on o ring.

 

[mknauss]

You would think the sound would be where the leak is. It must be on the suction side or you would see the leak when the pump is running. I know you replaced the gasket, lid, etc, but check them again. Especially the gasket. A speck of dirt can cause those to leak.

Once you have prime in the pump, does it stay full when running?

 

[garin33]

Thank you. I have replaced the lid and gasket a few times because the pool guy felt it was that. I have 3 pumps on my system and they are all the same. The main filter pump, the spa booster pump and the infinity edge basin pump. The other pumps work great with no losing of prime, no bubbles, etc. So I switched the lids with each and no change.
When the pump is running, there are no air bubbles and everything seems fine. If you turn off the pump, it will occasionally get a small bubble and then in about an hour its empty. I would not even care if the pump would prime again but once a few hours past, the pump will not prime unless I add water. So it must be reprimed every time it turns off. I would just leave it off but as you probably know that when the kids swim in the pool, water flows into the infinity basin and if the pump does not turn on and empty the basin back into the pool, it overflows and you lose lots of water. This infinity basin is a real pain and I wish I never put it in. Thank you for everyone's help.

 

[mknauss]

So if the pump remains primed and no air while running, but loses prime after being shut off, that normally points to the pump basket lid/gasket. When you have suction head on the lid, it does not leak. Remove the suction head (when pump is off), it leaks.
It may have deformed some when the pump ran hot? Or the mating surface between the gasket and pump is dirty?

 

[garin33]

Thank you. As mentioned, I have replaced the basket lid and gasket twice because I have two other pumps with same lid and gasket so I switched it with those and no change. I also did buy a new gasket and put magic lube on it, etc. My pool guy at the beginning thought for sure it was the lid or gasket so he even tried switching it, etc with the other pumps and then was finally convinced it was not that and thats when we replumbed the suction side and the pressure side. My only thought is that could it be the pump basket itself? I did check it to see if I saw any visible deformity and I see nothing. Of course, the only way I would know for sure is to get a whole new pump housing or possible switch the pump with another pump and see what happens. I guess if I switched the entire pump, it would rule out anything that has to do with the pump and then it must be the plumbing.
Sorry, yes, I cleaned both surfaces before putting magic lube on the O ring gasket.
Thank you. This is the first pool problem that I have had in 14 years that I couldn't figure out. Like I said, it seems like it should be sort of simple because it's not connected to the other equipment and piping. Its isolated.
Thanks again for all your input, very much appreciated!

 

[zea3]

You did have the pump run dry once and over heat. There may be a slight warp in the pump basket pot. Get some plastic wrap, lube the o-ring on the pump really well and put it back on the pump, then seal the lid to the pot with several layers of plastic wrap. Then run the pump and see if you still hear water or air after it is turned off. If you don’t hear anything run it a few hours and see if you lose prime. If this works then you need a new pump pot.

 

[garin33]

You did have the pump run dry once and over heat. There may be a slight warp in the pump basket pot. Get some plastic wrap, lube the o-ring on the pump really well and put it back on the pump, then seal the lid to the pot with several layers of plastic wrap. Then run the pump and see if you still hear water or air after it is turned off. If you don’t hear anything run it a few hours and see if you lose prime. If this works then you need a new pump pot.

Thank you. I will try that this weekend or sooner if I can get off work early. Yes, the pump did run dry and overheat since I started having the leaking issue. So it could be that there was a leak on the suction side and caused the pump to run dry and then caused the pot to warp, then we fixed the suction side leak but now there is leaking from the pot lid. I always thought there could be multiple problems which it makes it super difficult to trouble shoot. I actually hope its the pump pot because at this point, I just want to be able to fix it. Thank you again for everyone's help. I will report back.

 

[garin33]

Hello, a follow up. I tried to put wrap on the pump lid but when I turned on the pump, the water in the basket does not go to the top, is that normal when doing this? I decided to examine the plastic so I took the lid off and there was a hole in the plastic. I guess the pressure is too strong for the plastic so it ripped a hole in the plastic when the pump started to prime. So I tried do it again and it seem to happen again. It ripped a hole in the plastic and pump primes but the water only goes up about 2 inches are so from the top. However, water seems to be flowing at the usual rate. I just did it last night so I will check when I get home to see if it lost prime. But wanted to check to see if its normal that the plastic gets a hole in it and the basket does not fill up with water.
Thank you!

 

[zea3]

Well, it would seem that the plastic is getting sucked in for it to tear. Its blocking the leak enough to at least get a partial prime going. If you have duct tape you could try a couple of rounds of that to tape the lid to the pump pot and see if the pot fills completely. If that works then I would replace the pump pot.