Shaft Seal and Priming

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T

themotls

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May 20, 2017
21
Arkadelphia, AR
My Pentair Challenger pump will not prime, and so I've been in the process of replacing key gaskets and seals, including the shaft seal. I realized after installation that I used a PS-100 instead of the PS-200 and am now waiting on the PS-200 to swap out, but I'd lke to ask: would an improper shaft seal prevent a pump from priming? I understand that I don't want water running through the pump with the wrong size seal, and so I will not attempt to use it until I have the proper seal in place, but as I consider the possible reasons I can't prime, I wanted to eliminate this as a possibility.

Thanks to anyone who can help!
 
No. The seal is just spring loaded. I think if it somehow put the shaft in a bind, the motor would overload.

Can you tell if the pump impeller is turning? Any sign it is trying to pull suction? I would look for suction side air leak or open the pump again and make sure the impeller is still attached. What led you to change the seal in the first place? Cavitation from suction side leaks will damage seals.
 
I had massive water loss overnight last weekend, and I'm fairly confident the pump ran on air alone for hours. I worried that the heat might have damaged the shaft seal, so I replaced it. The impeller is turning, but I can detect no suction. Pump skimmer basket lid is intact, gasket is good, and properly lubricated. Diffuser gasket replaced and lubricated. I'm getting concerned that I have a significant leak in the suction-side piping leading from the skimmers to the pump, but I'm trying to eliminate other possibilities before I call in a pro.
 
Do you have an elevated spa? Mine is 18 - 24" above pool water level. If so, switch to spa mode and see if you can pull suction.
Is your pool level low? Below skimmer inlet? Do you have an auto fill?
Your pump lid may be the issue. I replaced my gasket and spent several more weeks chasing suction leak. Replaced lid - good to go.
 
No success. I replaced the shaft seal properly, turned the pump on, but no suction. I confirmed that the impeller is turning. Ran a considerable amount of water from a garden hose back through the inlet pipe and then ran my shop vac in it, sealed all around. SOME of the water from the hose came back, but not all, and eventually that stopped. My pool is completely green, and no green water came through the shop vac. I now believe I have a broken pipe somewhere in the return lines. Nothing is bringing the pool water back to the pump. Could it be something else?
 
Just replaced the pump lid and gasket, and water levels are solid (minus evaporation, which has been considerable of late where I am). Here's what's happened over the last few days: I was able to get water to pull from the drain with the skimmers sealed with a Jandy 3-way valve. After letting that run a bit I toggled the Jandy valve between the skimmer return and the drain return, and somehow managed to achieve full prime. Skimmers are pulling water and weirs are working normally. Air is still seeping in from somewhere, though, and an air pocket builds up in the return line significant enough to effectively stop the jets from working until the water builds back up in the pump. Then it resumes normal function with nearly full prime. Rinse, repeat.

I'm wondering if the Jandy valve o-rings need replacement. Would a seal failure with the Jandy be sufficient to create an air pocket that significant? This is quite a mystery for me. Thanks to you all sharing your insights.
 

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Okay, here's where I am:

1. Pump skimmer basket lid replaced, O-ring replaced and lubricated.
2. Inlet connector to pump skimmer basket replaced and sealed.
3. O-Rings on Jandy 3-way valve replaced and lubricated.

And here's what I'm getting:

Dropbox - File Deleted - Simplify your life

www.dropbox.com www.dropbox.com

If I backwash and rinse, I can get full prime when I return to filter, but eventually, the flood of bubbles comes in as shown above, I lose prime, and the pump has to build back up. I just can't figure out where the air is coming from. I'm losing hope that I can do this myself. Would pump failure cause this? Any theories are welcome. Thank you.
 
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You need to watch what is happening at the skimmer. It may be pulling a vortex that will flood the pump with air. If you can't find any other areas, you may have a broken pipe underground. You say weirs. Does that mean you have two skimmers? If so, close off one and see what happens. If If the problem goes away its the other skimmer or plumbing. If not, try the other one.
 
Tried alternating skimmers and the issue kept happening. I lubed the two drain plugs, and noticed that they had no O-rings. That seems like it could be an issue. I lubed the threads, but air is still coming in. I also see no evidence of water leaking from either plug.

Here's my question on a broken pipe: would I not see significant water loss along with the air issue? I have not seen a drop in water level inconsistent with daily evaporation. That's the one piece of evidence that makes me question a broken line, but my assumptions could be wrong.

This pump was here when we moved here in 2006, so it's certainly an older assembly. I'm upgrading to to VS later this summer, but I'm not ready to pull the trigger on the cost, so I'm trying to keep my current pump alive. Could any of these symptoms be indicative of a failing pump? When I pour water directly into the skimmer pot the impeller takes it straight up, so it appears to be working properly. I just don't know for sure.

I appreciate everyone's help. It's nice to be able to rely on a community of expertise to work through these things.
 
themotls said:
I lubed the two drain plugs, and noticed that they had no O-rings. That seems like it could be an issue. I lubed the threads, but air is still coming in. I also see no evidence of water leaking from either plug.
Click to expand...
Drain plugs are the #1 reason for suction side leaks. Get the o-rings. It is likely your issue for the suction side leak.
 
Pic attached. A few other things worth noting that might be instructive:

1. I set the Jandy valve on drain only and had pump surge for a few minutes before it caught up. Never achieved full prime.

2. I toggled to skimmers only; got the bubbles as I have when both are coming in.

3. I have put a garden hose in the inlet pipe to try and facilitate priming, and it's run for a solid thirty minutes with no evidence of water motion coming back into the skimmer; no bubbles coming up from the drain. Where is it all going?

4. I have no water around any of the gear in the picture. It's dry as a bone.

To recap:

1. Joint to skimmer pot has been replaced.
2. Skimmer pot lid and gasket has been replaced and lubed.
3. Jandy Valve o-rings replaced and lubed.
4. Diverter valve o-ring replaced and lubed.
5. Drain plug o-rings replaced and lubed.
6. Water level is properly set.
7. Skimmer weirs (2) have been removed.
8. The bubbles are clearly rushing in through the inlet pipe into the skimmer pot.

Calling all Pool Sherlock Holmeses! :p
 

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