Pentair pump stopped priming or passing water

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Some photos:

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One thing that interests me is the impeller has quite a lot of slop where it fits into the diffuser (see last three images). I wonder if this is not allowing air to come back into the front of the impeller. I don't have anything to compare it too. It has about 1/8 of movement, which I tried to illustrate in the last two images. Is this normal? Should I get a new diffuser and pehaps impeller?
 
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Here are a few more:

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So that "seal" the surface where the impeller fits into the diffuser divides the pressure side from the suction side. I'm not sure how that is a precision bearing surface, but it obviously has some amount of wear judging by the marks on both the impeller and diffuser. Perhaps if it is in water, that is enough to make sure it doesn't pass air.
 
With that pump, there should have been a o-ring (#8) on the outside of the diffuser which seals the diffuser into the housing. Was that missing or did you remove it?

The inside of the diffuser and the outside of impeller form a hydraulic bearing which remain separated by a small layer of water. This allows the water to recirculate between the pressure side and the suction side so the pump can prime.

Also, hopefully you are planning to replace all of the o-rings and seals while you have the pump apart. A seal kit will have everything you need.


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So the diffuser for a WFE-2 pump minimum price was $24, the impeller minimum was $30. Not bad, but I am unemployed at the moment and would like to be sure that is the issue.

This pump is my second Whisperflo pump. They are good pumps, the pull hard and are quieter than the original I replaced. The first one had a bearing, seizure, and I was unable to find any shop here that would repair it. The pump lasted about 3 years, I replaced with a new one of same make/model, and sure enough, that seized about 3 years in as well, same story. That time I watched videos on how to replace the bearing, bought a bearing puller, and got the whole job done for less than $20, vs. the $300 for a new pump. So lets just say I am motivated to repair it.

PS. All of the equipment in the photos is my own install. The original equipment on the uncovered pad was rusted out and I replaced, and put up a pump shelter as well.
 
The diffuser and impeller look fine to me. It is normal to have a little bit of scuffing.

But did you remove the diffuser o-ring or was it missing when you took the pump apart?
 
mas985 said:
With that pump, there should have been a o-ring (#8) on the outside of the diffuser which seals the diffuser into the housing. Was that missing or did you remove it?

The inside of the diffuser and the outside of impeller form a hydraulic bearing which remain separated by a small layer of water. This allows the water to recirculate between the pressure side and the suction side so the pump can prime.

Also, hopefully you are planning to replace all of the o-rings and seals while you have the pump apart. A seal kit will have everything you need.


View attachment 578239
Click to expand...

Thanks for asking. I removed it, there is a new one along with the seal kit I bought for it.

Yes, I am replacing everything. It all (the originals) actually appear in pretty good shape, but I am replacing them in any case.
So (referencing the video above) that space is acting as the "return port" mentioned in the video if I understand it.

So you think the impeller/diffuser is ok? Thanks.

Scott in San Jose, CA
 
samiam95124 said:
Thanks for asking. I removed it, there is a new one along with the seal kit I bought for it.

Yes, I am replacing everything. It all (the originals) actually appear in pretty good shape, but I am replacing them in any case.
So (referencing the video above) that space is acting as the "return port" mentioned in the video if I understand it.
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Correct!

samiam95124 said:
So you think the impeller/diffuser is ok? Thanks.
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That wear is pretty minor to me.
 
One thing I did not get a clear view of was the impeller ring on the inside of the diffuser. Just make sure are no large divots. A few light scrapes are ok.
 

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And while working on the pump, of course one of the bolts sheared off:

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The top damage is from my attempts to drill the bolt and use an extractor. the extractor is still there inside the bolt. It (of course) sheared off into the top of the bolt. Its wet because of all the anti-seize lubricants I attempted to put there.

Normally I would have trashed the motor and bought a new one at this point, but I am unemployed and poor. Note all of the corrosion around the motor. Some of this no doubt is due to the valve next to it that must be closed to operate the spa, otherwise the water in the spa slowly evacuates via the pressure side pool cleaner. Because the valve is manually operated, in short order that fitting comes loose and it starts leaking water next to the main pump. The fact that it is a salt chlorinated pool may exacerbate this.

Anyways, my next try is a technique I saw online where you take a nut of the same size and weld it to the top of the bolt shaft to extract it. Essentially you weld a new bolt head onto the broken stud. Then the motor casing gets wire brushed and painted to resist further corrosion. The pump is 10 years old, lets see if I can get more life out of it.
 
I solved my suction issue, and my Pentair Whisperflo pump has all the seals replaced. Pump primes, but does not move an appreciable amount of water. Was the pump damaged during the priming issue?

It started when I came home and found the pump running, but not moving water. The water in the pump basket was boiling (not an exaggeration). The pump was still able to run, turns freely, and I removed it and replaced the seals and generally refurished it. The suction issue was the Jandy valve in front of it. After redoing the seals in the valve, the system will prime, but the flow is incredibly weak.

I am wondering if the motor was damaged during the high heat when it wasn't moving water? There is no telling how long it remained in that condition, I set the pump time for 6 hours. Is there a way to test/determine if the pump is compromised?

Thanks,

Scott Franco
San Jose, CA
 
It is the impeller that moves the water through the pump.

What was the condition of the impeller when you refurbished it? You sure the impeller or shroud was not warped from the heat?
 
ajw22 said:
It is the impeller that moves the water through the pump.

What was the condition of the impeller when you refurbished it? You sure the impeller or shroud was not warped from the heat?
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Thanks for the reply. The impeller appeared undamaged to me. Its back installed in the system now. There are photos of it up in this thread. It spun freely after install on the shaft (as in the motor turned, I have to be careful how to put things). The shroud appeared undamaged to me. The motor spins without resistance. I replaced the bearings years ago, so I would have recognized a seized or compromised bearing.

This pump previously pulled like a train. The valve in front of it (see photo) was found to have a broken O-ring. It was replaced and reinstalled with lots of silicone grease. After that, the pump primes and moves water, but way, way down in flow.

Scott Franco
 
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Epilog:

The motor was replaced, which was a waste of time and money. Nothing changed.

I realized that one way to solve leaks in the system was to pressurize it. I looked up the burst strength of PVC plastic pipe, its like 1000 PSI or somesuch. I put the system under 15 PSI, and found several leaks in the piping, both before and after the pump.

Looking at youtube, there are several videos on how to do this. If you happen to find this thread, I can tell you definitively: trying to find leaks by running the system and looking for water leaks, blowing smoke into it, etc. These are a complete waste of time. The opposite of a vacuum is pressure. Even a low pressure like 15 PSI will immediately reveal any leaks anywhere in the system. You will hear it and feel it.

I have solar valves and spa/pool valves in my system, which can be set to "closed" and thus block the system for pressurizing it. A standard air compressor did the pressurizing, using the output regulator. The input can be done by the 1/4 fitting on the input strainer on the pump. In my case, the input weir to the pool happens to be threaded to 1 1/2 pipe, and a section of that pipe fitted with threaded coupling on one end and a 1/4 reducer on the other end with a compressor attachment did the trick. It cost about $5, vs the more than $100 "pressure test kits" on Amazon.

The net net is that the test indicated that the plumbing to and from the pump had several fittings that had come loose, probably with age. I installed all of it 15 years ago myself. Thus it was pulled out and redone. Now the pump is up and working again.
 
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TinFoilHat said:
There you go. Probably not enough glue 15 years ago. My plumbing from 2002 is still tight and dry but then I didn't install it myself.
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The plumbing is a mix of threaded and glued connections. Naturally the equipment is all threaded (pump) or unions (filter). The glued with threaded fittings means that it is impossible to tighten the threaded fittings, since the glued fittings cannot rotate.

Short story, it was the threaded fittings that started to leak. They were put on with lots of Teflon tape, which helps during install. I am guessing that over time with lots of vibration they give way.

The fitting on the pressure side of the pump could be fixed because of the union in line with it, but it actually was tightened several times and was in danger of being damaged at the pump. That one I took apart and reapplied with new teflon tape (lots of it).

The suction side had to be rebuilt, because it is sitting up against the front of the cabinet (originally it was open air, I added the cabinet) and had to make a 90 turn to get into the pump. Thus no ability to retighten and in fact no union there, because space there was very limited.
 

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