Possible pump motor bearing failure?

[kballard72]

Start up pump all is well 19 pounds PSI

20 minutes later drops to 5 and impeller gets really loud.

The thing of note since it runs 20 minutes it does not sound like a leak. My suspicion is perhaps the shaft of the impeller is loose or something or heat related causing a slowdown... Perhaps the bearings themselves but it is not really a bearing sound.

Interestingly prime is never lost no air bubbles, etc...

Dumfounded. Nothing is in the impeller but did not know at the time how to keep the shaft from moving to check its movement.

It is a hayward tristar and I noticed the white impeller ring (looks like a white bearing race) has numerous etchings as well as the neck of the impeller that it slides over....)

Its like the impeller is losing speed to maintain 20 but not its suction to maintain prime...

Go easy, this is just what I am seeing.

[PoolDoc]

Sorry for the delay in replying; I'm not sure why, but we've been hammered with traffic over the last 2 weeks and to put it simply, we cannot keep up.

It does sound like you have a bearing failure in the motor -- they are what would determine shaft alignment and movement. But I don't know how to tell you to check for that. I'll see if Mark (mas985) has any ideas.

[mas985]

Is the noise more of a screech or rattle/vibration?

Does the motor shut down when this happens (i.e. trips the thermal overload)?

If not, then the motor is probably not binding and it may be just the brass nut in the impeller has come loose/broken so it is slipping on the shaft of the motor. This would cause wobble and tear up the impeller ring plus make a lot of noise. When you turn the impeller, the motor shaft should turn too.

If the motor is shutting down, then it probably is a bearing although other things can bind the motor shaft including the impeller and/or impeller ring.

[kballard72]

replaced impeller, shaft seal, and the white wear ring that goes between the impeller and diffuser. let it all run before putting strainer half back on to make sure no odd noises in the reassembly. All good....
Put all back together... kicked on the hi speed and all was good for about 15 minutes as usual.. then the pressure drops from 18-20 down to 5 and a boatload of racket again. Not really a bearing sound though more like a clatter.

Observation #2, if I cut the valve half closed on the return side to force the pressure to build back up the racket stops. I think the racket is just cavitation do to whatever is causing the pump to not be able to maintain pressure.

Just bizarre, prime side stays full... pressure side drops... due to the time is still sounds like a heat thing with the motor, perhaps not bearings, maybe the motor itself is just doing something odd... it is a two speed emerson/hayward tristar. The motor was replaced once for previous bearing issues, which was a much different noise.

Are they clutched or anything where it would run on high but something slows the shaft... just stabbing in the dark...

[mas985]

There is a centrifugal switch in the back and if that is not operating properly, it could cause some issues so you might want to inspect that.

Are there any problems operating at low speed?

[kballard72]

Low speed seems to operate at as much pressure as high after it freaks out. So after high takes its split second nose dive from 19 to around 4 or 5... I simply kick it to low... the noise stops (which seems to come from the impeller area) and low speed is quiet like it should be. Once it is done running for the day I will let it sit... High seems fin on a cold start...

Kick it on and video what it is doing... a picture is worth a thousand words but youtube is priceless.....

[kballard72]

http://youtu.be/6zskny8Osfo

So at the beginning is normal pressure, never loses prime. I can close the return valve which will force pressure to go back up, but once the motor gets in this state it continues to run visibly rough.

At this point the motor seal, impeller and wear ring have been replaced... no change I suspect something internal to the motor itself.

[PoolDoc]

I don't know -- sound quality in the video is not good, and is very hard to listen to, but if the blue tubing in the screen cap below is passing air into the volute (chamber behind the pump strainer pot chamber) you'd get just that sort of effect. And, it's very, very common for tubing connected to pumps via the drain ports to cause that sort of problem:
https://lh4.googleusercontent.com/-_66SMlCf_ec/T8vHQ7OB3II/AAAAAAAADC8/EnxKZmR_Qiw/s800/Clipboard02.jpg

[kballard72]

That tubes job has been to pass air, its from the ozone generator and has passed some "air" since install 3 years ago.. But it is turned off while chasing this problem

And for the unit to run fine for the first 15-20 minutes repeatedly seems improbable to be related to the basket (suction) side. But that 15-20 minutes does have to occur after overnight cold.

[mas985]

It doesn't mater if the ozone line is off, you need to remove the line and put back the drain plug otherwise, you can't eliminate that as the cause. It definitely sounds like air is getting into the pump and if it is injected at the bottom, you may not see it in the pump basket.

[kballard72]

done. no change

[kballard72]

Steps so far the recap:

Removed ozone line and plugged with OEM plug per suggestion.
Impeller, seal, wear ring, replaced, though clearly unneeded (i already ordered before talking to the experienced folks on here)
The basket side has no visible cracks, etc.
removed motor from pump and it is quiet as a mouse when left running without a load

The main symptom is in a matter of seconds it starts making the racket like cavitation and the pressure drops at the filter.

On the suction side is two skimmers and a double drain.

On the pressure side is filer, chlorine feeder, split off to a return valve and a water feature valve.


The last things done prior to this occurring though this did not start when these maintenance items were performed

Filters pulled and cleaned
Valve to water feature replaced

Thanks All. At some point I guess i will be calling service, the fam will only wait do long on my shenanigans....

[kballard72]

Ran the pump again, it full primes and still making that racket and not creating pressure

If it is air, going after the last 3 parts that could be doing it out of sight between the basket and impeller...

Diffuser
Diffuser O-ring
O-ring between the two main halves.
go ahead and get a new one for the basket lid too


After that... may be time for a service call

[mas985]

Some things are harder to troubleshoot than others especially in a forum but it is still good to eliminate causes. One thing I cannot tell from the video, it moves around too fast, is what is happening in the pump basket when the noise begins and the filter pressure drops. Is there any change and do you see any air entering the pump basket? All the symptoms and sounds point to an air leak and I just want to make sure that I am not missing anything. Just for kicks, check the skimmer weir door and make sure it swings freely.

[kballard72]

Full Prime, no air in basket. If there is air it is somewhere between basket and impeller, unseen.

Skimmer is full of water when this is occurring.

======================================

door swings and plenty of water flowing

Would the diffuser O ring cause this issue? How about the diffuser itself?

The o ring between the two halves (exterior that the 6 bolts snug up), am I correct in that, that is pressure side and if an issue that would leak water...

======================================
Additional note: Shaving creme

Foamed up all the joints from the valves to the union, basket lid, and the two plugs... no signs of air being pulled through exterior suction side joints or gakets.

Basket side remains clear of bubbles...

It sounds like maybe the diffuser O ring is not letting the pump fully pressurize and causing the chattering? Or shooting blanks...

[mas985]

Would the diffuser O ring cause this issue? How about the diffuser itself?
I doubt it unless the diffuser was spinning inside the housing but you would have seen signs of that with the old diffuser.


The o ring between the two halves (exterior that the 6 bolts snug up), am I correct in that, that is pressure side and if an issue that would leak water...
Yes, any leaks on the pressure side would be squirting water.


Originally, you had posted this:

It is a hayward tristar and I noticed the white impeller ring (looks like a white bearing race) has numerous etchings as well as the neck of the impeller that it slides over....)
If the the impeller ring is not seated well or the wet end is damaged in some way, it may be possible that there is a periodic loss in pressure due to recirculation losses but this is just speculation at this point.

How badly damaged were the impeller ring and impeller and did you inspect the wet end housing for any cracks?

Also, is the filter filling up with air and do you see any air coming out of the pool returns?

[kballard72]

The impeller wear ring was slightly etched in comparison to the new. after seeing the new, that was probably normal wear. The impeller itself had no damage and kept it as a backup.

Diffuser was not replaced. It also would never be allowed to spin as the tristar has two screws holding it in place

Occasional bubbles at the returns, some air can be let off from the filter (though not seen in the basket).

Looked all on the strainer (suction) side and can spot no cracks..

[PoolDoc]

Sounds like you may need to exorcise the pump pixie! ;)

[kballard72]

It has crossed my mind to have the top two feet jackhammered, back filled, and go back to mowing a lawn....

[mas985]

Ok, I am starting to run out of ideas but I am not willing to give up yet. If you have a suction gauge, it might be helpful to find out what is happening on the suction side of the pump during this period of pressure drop. If the suction increases during this period, it could be cavitation that we are hearing and then we just need to figure out what is causing the suction to increase. If the suction decreases, it could mean that there is something occurring inside the pump besides cavitation. Most gauges with 1/4" fitting will fit the suction side drain plug.

If you want to give up, I completely understand. These types of problems can be very frustrating. :mad:

[kballard72]

No suction gauge.

I don't know if this observation would be comparable or just convolute the issue. I have a navigator vac that until this problem, for it to get into the flow spec per the hayward gauge: I would turn both skimmers off and drain valve 1/3 off, so the navigator would have max flow.

With this problem occurring to see if I could get the thing to sweep at all, with the drain almost closed off, skimmers completely shut down, could only get to low end of the hayward flow gauge...

Will see if I can locate an actual suction gauge.

[mas985]

Yes that can be very relevant. Do you have the same problem without the cleaner and with the skimmers and main drain fully open?

Reducing the flow too much to the pump can be problematic.

[PoolDoc]

Will see if I can locate an actual suction gauge.

Dixon Valve GL105 2" Steel Lower Mount Compound Vacuum Gauge (http://www.amazon.com/exec/obidos/ASIN/B0037QFK4K/poolbooks) @ Amazon

2 days, if you have Amazon Prime. You may also be able to adapt an automotive vac gauge, available at Autozone or some such.

[kballard72]

Yes that can be very relevant. Do you have the same problem without the cleaner and with the skimmers and main drain fully open?

Reducing the flow too much to the pump can be problematic.

What I am mean is that under normal circumstances, per the builder, was to turn the skimmers off when vacuming.. That always got the flow gauge for the vac to the low end. For 3 years. Just tweaking the drain a little, not all the way to a 3rd would get it to the high side of the gauge...

All I am saying is that since this problem started occurring, if i hook the gauge up to the vacuum port, skimmers closed and the drain almost completely shut off will get it the gauge up to the low/mid point...

[kballard72]

While it may not seem probable, the only thing left is diffuser, o ring in the diffuser, o ring on the lid...

no air seems to occur before the pump on suction side (plumbing issue)

the motor when removed is quiet as a mouse.

Sooooooo out of ideas at this point.... unless there is a hail mary... the robo vacuum already tells us we are losing suction power.. on High, with valves fully open no robotic movement. close skimmer, almost close drain, and robot barely moves.

Any final hail mary...

[mas985]

Again, does this only happen when the cleaner is attached and the suction ports restricted or does it also happen without the cleaner and with all suction ports wide open? This is a very important distinction.

If it is happening only with the cleaner attached, the cleaner hose maybe collapsing which is causing the oscillatory condition. Try removing the cleaner all together and open all suction ports and see if this continues to occur.

[kballard72]

The problem happens under normal usage. skimmers on, drain on, returns on.


The cleaner port is simply an example of one place I do have a gauge for. With a single 4 foot hose plugged to the port, and the flow gauge on the end, I can see that it is not drawing the suction it was say a month ago... But that is only to SEE what it is doing. The vac is not the issue...

[kballard72]

Diffuser came... having a point of reference, new versus old... it was clear the old one was worn. Where the wear ring butts up against the difuser used to be a ridge about 1/4" wide by 1/8" tall, not only was it gone but it was a valley on the diffuser.

SO, I thought viola, this is the problem we have been looking for... Replaced it... kicked on the pump all is wonderfully quiet as usual on start up.... basket fills up, all air purges... nice and clear window.... and 5-10 minutes later, so long pressure, hello irritatingly loud chatter....

thanks for all the insight, but it must be time for someone on-site I guess...

[mas985]

Unless you got that vacuum gauge. ;)

BTW, does the flow rate out of the returns decrease or increase when the pressure drops?

[kballard72]

it definitely decreases. as well as the water feature, which is simply two returns on the sun deck that point straight up.. they drop from 2 feet high down to 6 inches....

For that wear ring to have carved away an 1/8" of plastic off the inside of the diffuser, is that a normal amount of wear?

Well clearly there were items worn out and they have all been redone, and seems to be casualty symptoms of something else going on. Impeller, wear ring, and now diffuser. All of which were visibly worn with the diffuser seeming to be abnormally chewed up. Either way all internal parts except the motor are shiny and new.

The odd thing is the split second change, as if something "gives" like suddenly the pressure is just gone... Its not gradual... after being off for awhile you can turn it on, all will be well, than bang, pressure dives and noise starts.

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.

[BigDave]

Is it possible that you have some flex PVC or other soft wall piping that may be collapsing under sufficient vacuum and time.

[kballard72]

No flexible piping in the system. Oh I wish it were the obvious solution. dry skimmer, etc.... covered already though....

[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/hphotos-ak-prn1/538287_10151740591072837_2128470668_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?

[kballard72]

So on a whim I went and got fresh rubber parts lube from leslies.... In case my tube from last season was broken down... yeah much different consistency...

One more time for giggles i gutted the pump. lubed up the ring between the power half and suction half.
lubed the pressure side union
lubed the suction side union
cleaned the lids groove with soap and water to get anything out of it.... lubed the lid ring again..
lubed the diffuser ring
reassembled...

Under no load meaning main and both skimmers wide open, has been purring for an hour now on high speed, I have yet to close skimmers to try and vaccumm this is the most I have gotten wide open in a month... water feature is flowing full bore... I may just bask in the glory of having high spped and stick to the idea of buying a robot to clean...


down to two culprits that lid is shot and thicker silicon bought me a little more sealing power, though the seal is new... or the union is not quite lining up... will check and retighten.....

[mas985]

Also, check the pump drain plugs.

[kballard72]

funny thing... 100% of the time I once the sound starts... stop pump... do one simple thing...

so after awhile on high today, skimmers, main, returns, and water feature wide open. It finally started doing it again...

turn pump off, open strainer lid, close strainer lid.... restarted and pressure instantly returned to 20... no chatter and off&running again......

Before removing the lid I turned it off and on to see if the action of off/on does it... no, still chatter... removing and reseating the lid seems to alleviated its troubles consistently at this point... how long varies has gone as long as two hours that I was outside before switching to low... or simply turning off...

I want to say today was about an hour before chattering returned... but still reseat the lid and viola!