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seized keg king silver pump

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Adr_0

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Bearing failure analysis, let me just grab my mansplaining hat, jodhpurs and cane...
Causes of bearings going out like this could be for many reasons, but for a low cost Chinese item like this I'd wager they probably use cheap bearings that will have a higher failure rate than better ones. Which is pretty damn obvious I suppose. It's likely a bearing defect at manufacture that has developed to the point it won't spin properly. Contamination or improper machining are the most likely causes, as a small piece of plastic or similar falling into the bearing during assembly (these are hand assembled) causing some sort of plastic deformation of the elements or races will lead to gradual decline and eventual failure. Could be a machining issue on the cage, accidentally forgetting to grease it during manufacture, excessive preload on assembly, mishandling, and various other boring reasons. At the end of the day almost all manufacturers have an expected product failure rate and I would say this is no different. If it's the bearing.

That said this is the first issue I've heard with a Kaixin/KK pump, they've been remarkably reliable for their price and performance.
Shouldn't we see more 'energy' when it's running though, i.e. more crunching, vibration, when it's up to speed? Hence my pretty poor query about whether it's more of a rasping.

I'm also surprised that something behind the magnetic sleeve - which is directly coupled to the shaft - has such an impact on it. Bear with me here... but if the secondary winding and capacitor are A-OK, it should have enough starting torque to overcome this. Issues seem to come up when the impeller has something in it - and there's no direct coupling of the impeller to the shaft/sleeve, it's through magnetic inductance/grabbiness, so it's more likely to catch and not be able to start.

But he's reported crunchiness/raspiness when the sleeve is rotated, so yes there is likely something behind the magnetic sleeve. Hence the suggestion of cockroaches... but since the magnetic sleeve is directly coupled to the shaft, I thought there'd be enough torque to overcome this. *shrugs* I guess not?
 

pcqypcqy

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OK, persuaded the magnetic drive off over lunch with a pair of multi grips. Probably did the magnets no favours. Pictures attached for reference if anyone else is playing along at home.

Interestingly, the shaft still struggles to get going now, even with no weight on it.

So we're going to have to attack it from the other end now.
 

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TheWiggman

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Could be many things Adr_0. I haven't read that issues occur when the impeller's in, note pcqypcqy said he had to physically push the magnet to get it going hence the volute was off. 'Sticktion' they call it (a word I hate) at the place I currently work, which is their layman's term for high static friction which comes unstuck with enough force.
As you're no doubt aware depending on how a bearing wants to go sometimes they give you 2 mins warning and BOOM seized, other times they'll grumble for months then look reasonable when they're pulled apart. All depends on what's physically occurring in the bearing.
There looks to be a lot of foreign shit behind the magnet there pcqypcqy so my money's still on the bearing. I don't know how that all got in there. Interesting to see it pulled apart though.
 

Adr_0

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I have heard that term a lot, and thought it referred to 'sticking and friction', primarily with control valves - eg rough movement, sticking, holdup/overshoot. I'm pretty sure that's why they invented C4 - seems like a less painful way to deal with that stuff.

FFT analysis gives me a semi. I have seen many great examples, but two stuck out: finding an issue in a lube pump on a turbine, planning the shut down and replacement, coming back up again - roughly $10k including labour; the second was on a drive end bearing on a turbine, the CM guys flagged it, a few people in power on the project thought it would be alright, then it lunched itself a couple of days later costing about $30mil in new turbine, labour, production, re-mapping...

So moral of the story pcqypcqy - replace it so that it doesn't cost you $30mil.
 

pcqypcqy

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I can't see the damage bill racking up to quite that amount.

But maybe as far as $300 to go up to a march pump or similar. Or a hobby mig welder to teach myself how to weld and build myself a 2 tier brew stand :D
 

pcqypcqy

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Righto, with the magnetic drive off the front, I took the back end off and sliced through the sticker. The front portion came straight out.

Detailed photos attached.

The drive shaft spins quite freely in its bearing, so I think the bearing itself is actually fine.

Looking at the back end of the drive shaft that sits right at the back of the pump, there's a heap of shit and rust here. I believe this is the culprit, and must have occurred when some wort got in the missing plug hole on the bottom of the housing. I mount my pumps vertically, so anything that got into the drive shaft would end up right at the back.

I'm going to clean this up a bit, re coat it with some PTFE and see what happens.
 

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pcqypcqy

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And this appears to have worked. Been testing the last hour or so, flicking on off, running it for a while then doing it again, leaving it a while then doing it again. Has started fine each time.

One tip if doing this yourself, ensure when you remount the magnetic drive on the drive shaft, you push it so that the end of the drive shaft is flush with the base of the magnetic drive. Otherwise it won't sit at the right depth relative to the black plastic parts, and you'll just get a heap of friction in there. Once I worked that out I was off and racing.
 

pcqypcqy

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Should dedicate that meme to @klangers who said these units aren't serviceable :D

(just kidding mate, I know most people aren't as hell bent as I am at pulling things apart and putting them back together).
 

pcqypcqy

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I did not. It needs another pull apart and a proper grease (ptfe isn't working), so I'll try to take some more photos.
 

pcqypcqy

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This came good and lasted for a brew. Seized again right at the end of the sparge, so was quite lucky.

I will pull apart and apply some proper grease and see if that fixes it.
 

pcqypcqy

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So the saga continues. I discovered a new piece that can be removed, which is the rear part of the housing.

When I took a look inside, it's rusted to all hell, so I really must have dribbled something good in there on the first use. Surprised it didn't short to be honest.

Anyway, tried cleaning it all with contact cleaner and greasing it, but not having a great deal of luck. It seems now that in all my attempts to pull it apart, I may have knocked the shaft off centre, and now I'm getting contact between the shaft magnets and the motor mangnets.

I'm also finding I can't get the magnetic drive off the shaft again very easily either (was very easy the first time). So as a result I wasn't able to site the bearing for those that asked.

Looks like I'm building a quick timber stand and turning it into a 2 tier system for a while.

Does anyone have advice on dealing with the capacitor? I'm reluctant to do too much more in case it shorts on me. It's a 1 micro Farad capacity, at 240v I assume. Not sure if that's an amount of power I should be worried about or not.
 

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mofox1

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At this point it's okay to give up. ;-)

Edit: I do love the effort that has been put into this. Exactly the sort of thing I would do, know it's not worth it, and yet occasionally pull off a MacGyver and feel ridiculously accomplished.
 

pcqypcqy

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At this point it's okay to give up. ;-)

Edit: I do love the effort that has been put into this. Exactly the sort of thing I would do, know it's not worth it, and yet occasionally pull off a MacGyver and feel ridiculously accomplished.
Like a dog with a bone, I'll keep gnawing at it until I break it or fix it. I'm learning in the process as well, so it's enjoyable (until that capacitor zaps me probably).
 

malt junkie

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Were you able to get to the barring? If you do let us know how you get on for a replacement.
 

pcqypcqy

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Were you able to get to the barring? If you do let us know how you get on for a replacement.
Not yet, but the bearing is fine. Once I separate out the rolling parts from the housing, it spins very freely.

I'll try to get a happy snap of it if I ever get in there.
 

pcqypcqy

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Did you get the bearing number after all that effort?
Since the earlier posts, ivd been using a two tier stand and getting away with just the one pump. But last brew it starting seizing as well, so here we are again.

Managed to get a close look at the bearings, the brand is C&U, and the number is 626Z (or Z929).

Now I have both pumps apart, it seems the bottom bearing is crunchy on one of the shafts, but on the other it's the top bearing.

Does anyone know how to take the bearings off the shaft, and if it's easy enough to get replacements (or swap them over so I can have one shaft with 2 good bearings).

The root cause of this seems to be that the housing isn't properly waterproof, and the occasional dribble of wort gets in and the problems start from there.

I mount mine vertically below by vessels so that they self prime. Not sure why this has happened to both of mine and not anyone else, will need to work that one out.
 

TheWiggman

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It'll be a Z929, bearings always have the letter as a prefix. A quick search on Alibaba yeilds price <$1 each. Try CBC, SKF or any bearing supplier and they may either have them or can get them in stock.
The old ones will be a clearance fit on the shaft and with some force will slide off. If you know someone with a bearing puller it'll make the job a lot easier. I recommend measuring how far on from the end of the shaft they both are in case there's no shoulder on the shaft to locate the bearing.
When to fitting the new ones make sure you don't just bash it on with a hammer as this can damage the races, slide it on physically or use a nail punch on the inner ring carefully on each side (or ideally, a bit of tube).
 

earle

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Two seized pumps for the one brewer. I think the cause is obvious? :fallingoffchair:

Ha ha, shit on two forums is twice the fun.
 

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