Pump running but not pumping - curious impeller part

Sep 27, 2014
11
Dickinson, TX
This is my first post but I am sure I can get some help here. I am following the TFPS methods as near as possible and have been incredibly pleased with this great resource. Thanks to the organizers.

Here is my problem. I have an in-ground pool, about 30-40,000 gal. Pool was built in late 1960s, maybe - when house was built - so I don't know the exact age of the equipment. It has been mine for 4.5 yrs. About a month ago I found a very rusted bolt-like thing in my pump strainer basket. A couple of weeks ago I realized that my pump (Century Centurion 1 1/2 HP) was running but not pumping through the filter (0 psi pressure and when I opened the air bleed valve it actually seemed to be sucking rather than blowing). This morning I finally had time to open up the pump (which seems not to have any manufacturer label - but it looks a lot like the Pentair Dyna-Pro schematic I found on-line) and motor and look for the problem. It appears that the motor has a female thread at the "impeller end" of the shaft and the impeller (C105-236P) has female threads on the side that faces the shaft. I am apparently missing the threaded coupling that should attach the two parts. I am having trouble finding a source on-line that shows me that type of connection and my local pool store kid was useless...without a SKU for the part. That was apparently what had worked its way - upstream ? - to basket...???

Any one familiar with this type of impeller set-up and/or any guidance on where to look for the part?

Thanks in advance for the help.
 
Welcome to the forum.

The impeller should have it's own shaft which screws on to the motor shaft but there is also a screw that goes into the end of the impeller. There is no coupling so if the impeller doesn't look like the picture, that part may have broken off. Also, the motor should have a threaded male fitting on the end, not female. If both look to be female, then the impeller shaft may have broken.

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This schematic shows all the parts:

http://www.pentairpool.com/partslists/pumps-inground-dyna-pro-dyna-pro-e-pumps-55.htm
 
Welcome to the forum.

The impeller should have it's own shaft which screws on to the motor shaft but there is also a screw that goes into the end of the impeller. There is no coupling so if the impeller doesn't look like the picture, that part may have broken off. Also, the motor should have a threaded male fitting on the end, not female. If both look to be female, then the impeller shaft may have broken.


Hi Mark,

Thanks for the reply. That is actually the schematic I had found on line that looks like my pump housing but the connections of the impeller don't look quite right. Both sets of threads are female and the edges look so smooth that I can't imagine that it broke off. I am thinking this is an old set up that is going to be hard to track down.

ron
 
Actually, the last one is the seal. You have to remove that to see the motor shaft. It looks like the other half of the seal is missing too.
 
The seal should not have a thread inside of it. It usually slips over the impeller shaft. That is probably the impeller shaft stuck inside of the seal.

I am not sure what you have going on there. If you are interested in repairing it, I would get a new impeller, impeller screw and seal kit. But now might be a good time to downsize the pump and just get a smaller impeller.
 
The shaft is the small round metal part inside the black ring. The black ring is the female part of the impeller that is broken off of the impeller. Pull the seal off and unthread the broken impeller part from the shaft. get a new impeller and seal and re-install.
 

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Thanks (both of you guys) for the help. I took more things apart and y'all are right. The rest of the impeller shaft sheared off and apparently rub itself smooth so it didn't look like it. I have ordered a new impeller and seal and hope to have them assembled by next weekend.

Much appreciated!
 
Because most people have pumps that are too big for their pool. Downsizing the motor and impeller results in large efficiency gains (lower flow provides better filtration) and substantial cost savings. As the HP of a pump increases, the wattage it draws does not increase linearly. Not sure that it's exponential, but it's certainly a curve.

Please put your pool and equipment info in your signature. We (and by we I mean the collective we...I'm definitely not a pump sizing expert) can help you make a decision about pump size that might save you some money.
 
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