Possible pump motor bearing failure?

[mas985]

The noise which sounds like rocks clattering, is what I have read to be the sound of cavitation. So that may just be s symptom of the pressure drop and not the cause of it. One way I have found to make the noise stop is restrict the returns to cause the pressure to build up some. I dont leave it like that, just something I noticed.

Those are the symptoms of cavitation and if a line is collapsing as Dave suggests or there is some sort of periodic blockage, increasing the return head would allow it to expand again (reduce the suction head). A suction gauge would help to confirm that.

Also, the video does not show the suction side plumbing very well. Do you have a check valve anywhere? Sometimes the flappers can break and cause similar symptoms.

[kballard72]

There is one check valve side after the filter and before the 8 tab chlrine feeder...

Ok... Towel, thrown... calling service....

[PoolDoc]

For my sake, and especially, for Mark -- when you find out what the problem actually was, please let us know.

[kballard72]

Yeah, all the input insight is appreciated.....

Extremely frustrated, as I've rebuilt engines, worked on 100,000 dollar laser medical printers.... and a freaking pool pump and some plumbing has me stumped....

It's gonna be a piece of dang mulch flying up and getting stuck in one of the T connectors and sinks back down whenever the pump shuts off, thats causing turbulance in the flow.... Something I cant see without cutting plumbing... And still tempted to do since one of the valve handles snapped off today (while opening it for the 100th time this week) . cheap junky 8 dollar ball valves.... But the grand wizards that built the thing butted all the connections in such a manner... I have to cut out all 4 valves on the suction side and redo the whole darn run...


There is not enough pipe space to splice....full redo...

https://fbcdn-sphotos-a.akamaihd.net...28470668_n.jpg

[kballard72]

OK so where have things progressed...

Well two valve handles broke off so cut the plumbing up and replaced 4 junk ball valves. While the valves were out blew out the lines not much in the way of debris...

Set the new valves... cranked it up... purred like a kitten.... for about 30 minutes..... this was a pump that had been off for 2 days COLD........

air bubbles purged in a bout 5 minutes to a nice primed clear basket side.....

I wasnt paying anyone for valves and figured it would be a great time to remove any debris in the lines... The vavles were all suction, main drain, two skims, and vacum....


So seems to me if air related I would see air... The timing would be consistent.

The problem appears directly related to how long the pump has sat to get cold...

The pump itsel has had everything on the suction side replaced, gasket on the basket lid, gasket on the coupling to the valves, oring on diffuser, diffuser, impeller, wear ring, shaft seal... basically everything except the motor....

[kballard72]

So when Pressure side is on 18-20 psi

vacuum is 6-7 in hg

ran for about 5 minutes before the noise and filter pressure dumps to about 10. basket vacuum drops to 1 or zero..

Another thing I notced this stops after I reseat the lid.... without waitig for a cool down... I replaced the oring but do the lids go bad? I cant see anything... I slathered the o ring really good with lube and got about 20 minutes of vacuuming before the noise started again. If there are air bubbles they are crazy small...

To vacuum just as I have done for 4 years:
Kill the two skimmers, turn cleaner valve on, to get the vacuum moving

While vacuuming the pressure stayed around 18 at the filter... vacuum climbed to 15 in hg at the basket. as a result of the skimmers off.

Then when the noise kicks in everything dives...

Lid Assembly? Any votes?

[mas985]

The pressure drop in both the suction and pressure side indicates a problem with the pump itself and for some reason the pump is not pumping as much water during this period. This could be caused by several things but since you replaced so many parts, I suspect it is a lot air entering into the pump chamber.

The lid gasket can go bad so the pump lid does not seal. But if that happens, you should see air in the pump basket. Also there can be cracks in the lid or even the pump housing which can draw in air into the pump. This can be due to a lot of air entering the pump. If that is happening, then the filter should fill up with air and you should see air coming out of the returns. Most of the time if there is a crack in the pump housing it is on the pressure side so you can easily see water leaking out but if it is on the suction side, it will be harder to detect. Does the pump leak any water when it is off? Also, when you used the shaving cream did you put any on the front half of pump housing?