seized keg king silver pump

[pcqypcqy]

You say you rewired it... Did you touch the starting winding at all, where that tape is?

It should have four wires plus earth (two of which are the starter windings, 90° out of phase).

We didn't go into the metal pump housing itself, just attached a new lead to the wires that were in that little plastic housing at the back.

 

[Adr_0]

We didn't go into the metal pump housing itself, just attached a new lead to the wires that were in that little plastic housing at the back.

Yeah that's the one. If you just went like for like that's ok, I can't remember if there's a capacitor there though. If the capacitor was shot - from overheating during soldering? - or there was a dry connection anywhere on this secondary winding, it would have issues starting. And I don't mean to suggest you've done anything to the physical windings, but any issues with the connections in the plastic housing would do it.

A mechanical/rubbing issue wouldn't help, but I would think this would present issues during running as well.

 

[pcqypcqy]

Yeah that's the one. If you just went like for like that's ok, I can't remember if there's a capacitor there though. If the capacitor was shot - from overheating during soldering? - or there was a dry connection anywhere on this secondary winding, it would have issues starting. And I don't mean to suggest you've done anything to the physical windings, but any issues with the connections in the plastic housing would do it.

A mechanical/rubbing issue wouldn't help, but I would think this would present issues during running as well.

There is a capacitor. All connections were done like for like using crimped connectors. Can't remember if there were already crimped connections in there, or if we cut the wires.

 

[TheWiggman]

Two things of note -

• Stopping and starting a few times can get it going, when it's stuck pushing the magnet gets it going
• Lube behind the magnet seemed to fix it

There's a friction issue on a seal or withing the DE bearing. The magnet looks like it's secured to the shaft with a cap screw, so next time it happens undo the cap screw and remove the magnet. Whatever you see behind there will likely give away the issue.

 

[pcqypcqy]

Two things of note -

• Stopping and starting a few times can get it going, when it's stuck pushing the magnet gets it going
• Lube behind the magnet seemed to fix it

There's a friction issue on a seal or withing the DE bearing. The magnet looks like it's secured to the shaft with a cap screw, so next time it happens undo the cap screw and remove the magnet. Whatever you see behind there will likely give away the issue.

The problem with that screw is no tool of mine will engage it. It's either a very specific allen head, it has been stripped during manufacture (as I haven't even tried yet), or it's a rivet.

Either way, I can't take it off from this end, which is why I'm trying to get at it from the back end.

 

[TheWiggman]

I see. They're largely waterproof so there's a good chance the cap on the back was glued on after the rotor was installed. I wouldn't remove that to see if you can unscrew from that end.
The magnet will need to come off to disassemble the pump and inspect / do anything around the drive end bearing. I've got a nice selection of screw heads at home so I'll check my pump out tonight (hopefully) and let you know if I have any success. If it's riveted then too bad, keep on-a-lubing until she spin no more.

 

[pcqypcqy]

I see. They're largely waterproof so there's a good chance the cap on the back was glued on after the rotor was installed. I wouldn't remove that to see if you can unscrew from that end.
The magnet will need to come off to disassemble the pump and inspect / do anything around the drive end bearing. I've got a nice selection of screw heads at home so I'll check my pump out tonight (hopefully) and let you know if I have any success. If it's riveted then too bad, keep on-a-lubing until she spin no more.

That plastic cap was pretty rubbish, and never water proof I suspect. We butchered it anyway to re-do the lead, and I periodically inspect and retape it to minimise the water that gets down there.

So not afraid to attack it from that end.

 

[Adr_0]

Hopefully there's not something behind the magnetic sleeve. There could well be if there is friction or sticking when you try to spin the sleeve without power, including in various orientations, pushing in/pulling out, etc.

Oooh, this is exciting! I want to rip my pump apart again and see if I can get the motor assembly out.

Can do you do some checks on the wires? You should have something like the following:

So you should, with a multimeter, be able to verify each side of the capacitor back to the Live and Neutral has resistance/continuity. You should have 4 different resistance measurements when you check each side back to Live then Neutral, and certainly should have continuity for each measurement. If you don't, you have a break in the line somewhere.

You'll have to pull the capacitor out to actually check it, so I'm not sure that it's worth looking at that yet - but you could visually inspect it: make sure it's not bulging/split, no hardened **** is leaking out and no evidence of burning.

 

[Tony121]

If the pump doesn’t start initially but will run with a flick of the impeller then I would think the capacitor is shot - as I dare say it would be a start capacitor.

Edit: Read most but skimmed some parts so apologies if this has been flagged already.

 

[hotmelt]

I think to get the magnet off, look in the hole and rotate the magnet you'll see two grub screws.

 

[TheWiggman]

Bang on ^^^^ 2.5mm Allen key required.
To separate the motor the screws come from the back, so if you did want to pull it apart you'll need to take the cover off. Tony's probably on the money though it is suspicious that applying lube has allowed it to run fine ever since. Maybe a coincidence.
PS: cheers for the motivation because the piece of chux cloth I just found wrapped around the impeller journal might explain some flow issues I've been having.

 

[dblunn]

Mate, sounds like the start winding could be rooted. Single phase motors don't produce any torque when they are not spinning, hence the start windings to simulate a poly phase motor to get it turning. Have you checked the continuity of the start winding?
Regards, Dave

 

[pcqypcqy]

Definitely something sticking in there. I checked my other pump and it freely spins when switched off, whereas this one takes a bit of force to break the friction. I've noticed there should be a rubber cap for the hole on the bottom, and the sticky pump is missing this. Maybe I got some wort in there at some stage.

I'm running with this for now over the wiring and capacitor because of how it feels when I turn the wheel. Crunchy almost.

I saw those grub screws this arvo, but was not sure what to use in them. Just got them out with the 2.5mm Allen key as suggested. I was able to slid the magnet drive a bit but not remove it. I sprayed some PTFE in the holes left by the grub screws and that's already made it a lot smoother. Still not starting first time every time though.

 

[TheWiggman]

If it's almost crunchy then 99% sure it's a bearing. If you completely remove the grub screws the magnet should come off with a bit of force. Undo the screws at the back and the housing will separate, allowing you to slide the rotor out. There'll be tiny bearings on it that should have a number written on them, use your web skills to find some new ones. If you're lucky a bearing store might be able to supply some. But I were you I think I would be looking for a new pump.

 

[Adr_0]

If it's almost crunchy then 99% sure it's a bearing. If you completely remove the grub screws the magnet should come off with a bit of force. Undo the screws at the back and the housing will separate, allowing you to slide the rotor out. There'll be tiny bearings on it that should have a number written on them, use your web skills to find some new ones. If you're lucky a bearing store might be able to supply some. But I were you I think I would be looking for a new pump.

Do the bearings go in these things? Is it just one of those probability things that 1 pump in xx won't have enough grease and will run dry?

Crunchy could be Coco pops too. Or cockroaches. Could be raspy rather than crunchy.

 

[pcqypcqy]

Two options before a new pump:

1. fix this ******* thing, which is turning into a fun exercise and might end up being a good sticky on this forum for anyone else who wants to play with it.
2. add a second tier to my brew stand and stick with the one pump.

I'm able to slide it out about 5mm, then it's catching on something. I haven't had a real chance to apply force to it yet, so will try that over the weekend. But I note that it already spins a lot more freely when it has slid out a little bit.

 

[Adr_0]

Two options before a new pump:

2. add a second tier to my brew stand and stick with the one pump.

don't do it! God has blessed mankind with the ability to convey fluid by plugging a black hose into a wall socket, so why not use it?

 

[pcqypcqy]

it is option 2. Option 1 is to use tools and do manly things and fix/break the pump first.

 

[TheWiggman]

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.

 

[malt junkie]

You missed option 3.... Start a BB or have someone else start one!