Tunze Stream 3 (6150) - issue with bearing disc

[aj68]

Hi,

I have a big issue with the bearing disc of my tunze 6150 (see picture):
The pump is running about 5 months without any problem.
Due to a problem with algae I have to clean the whole pump yesterday.
I noticed, that there was a black abrasion on the pit of the bearing disc.
But I reassembled the pump and the pump runs with a few start-up problems but then quit and as good as before.
Today morging I recognized that the pump doesn't run anymore.
So I disassembled the pump again and noticed that the abrasion was more obvious. Putting bearing disc and rotor (with ball) together, one can see, that there is no gap between them anymore. The rotor rubs directly on the bearing disc.
Has anyone had the same experience?

Andreas
(Please excuse my bad technical english...)

[rvitko]

The disk is badly worn, the side slots are missing and this wear is the cause of the pump not running, I had this happen myself due to sand getting in the pump. If you replace this part the pump will work perfectly again. There can be only 3 causes of this issue.

1) Any sand or abrasive entering the pump.

2) Test running the pump dry for even some seconds will damage the bearing

3) The bearing tension is set incorrectly either due to a modification or possibly the bearing support is broken, the details of setting the bearing tension are covered in the manual. Since it worked for 5 months and from my experience I lean toward 1 or 2 being the more probable causes, the bearing tension is carefully set at the factory so unless it was modified it should not be changed but it would be worth checking if this support was broken.

[aj68]

I can absolutely eliminate 1 and 2. And I have never opened the pump from the other side.
I have removed the rotor just for cleaning it (due to an algae problem I have in my tank).
And this was a hart job due to the extreme magnetic force there. Especially when assembling.
I checked the holder of the disc and it seems to be ok. Even the kind of screw for regulating the distance. I do not dare disassemble it due to the existing guarantee.
So I will send it to tunze to repair this, and I'm curious about what they say...

[rvitko]

You are able to disassemble the pump within the warranty terms, you can break it down as shown in the manual and this is considered maintenance, only modification would void the warranty. Please consider that you can just request a bearing by email and even buying it, it is a $4 part, much less than sending a complete pump and much faster. If at any point any sand dust was sucked into the pump it will cause this damage, it is not due to opening the pump or doing anything other than some sand suspended in the water getting in.

[aj68]

I have only very few sand in my tank, the pump is far away (20 cm) and I have no digging fishes. Sure, it's not impossible...

Thanks for your hint to buy the disc only. But I assume, that the ball and/or the plastic bearing inside the rotor is defect, too.
There ist no gap anymore between the ball and the disc.
The pump is a critical part and I want to ensure, that everything is ok...

[aj68]

Tunze has replaced the bearing disc and the rotor within a week and without any charges.
Absolute perfect service!

[rvitko]

Great news, probably based on the repair the rotor was out of balance and the wobble damaged the disk.

[JWClark]

Interesting, I seem to be having the same problem now but my disk doesn't appear to be worn. Will take apart again today to double check. Cleaned yesterday as it was stopping and it ran for a bit then stopped. Last night, when the lights went out, I noticed flashing LEDs on the side--inside the housing shining through. At first, I thought it was sparks, then realized it was a set of LEDs in a row w/ the bottom one flashing and others streaking up to a red one periodically (red only after unplugging and reconnecting power).

My unit always seemed to vibrate pretty good and there appear to be a few scratches at the top of the magnet so now I am wondering if it wasn't balanced right. Been running it for 8 months.

[rvitko]

Take a very close look at the disk, possibly post a photo, where the damage will appear is as discoloration at the very bottom and as a melted appearance at the side slots. It is possible that the drive unit was out of balance, this was common on earlier units and within reason is not a cause of failure, the disk failing though will always cause a problem. I do have all parts on hand and we can certainly get this resolved.

[JWClark]

Here is a pic. Think what looks like sand in the slots is probably plastic so I think it may be shot. Thoughts?

[rvitko]

It is hard to tell from the photo, if the bottom cup is worn enough that it is translucent and appears very thin, this is likely the culprit.

[Alma Knack]

Unfortunately, I am also having the same problem. I get the flashing LED’s, a whine noise, wobbly attempts to start and the occasional successful start and occasional failed starts. I’ve been through one disk already and the new disk appears marked with a black ring similar to aj68’s picture. I would like to know if my pump is out of balance. My pump has never ran dry and is a good 10 inches from my sand. Occasionally I need to leave my tank for 2 weeks at a time or longer and my tank sitter will not be able to replace the disk. Should I send it in to check for proper balance? Thank you!

[rvitko]

You are welcome to send it in, but you may be able to diagnose this yourself. The cause of the immediate issue is definitely the bearing, but unless sand is getting in the pump or it has run dry, either the bearing tension needs to be adjusted or the support for the bearing is broken. The manual shows how to adjust the bearing tension and before doing this, check that the support cage is not cracked, if it is broken, this will make a tension adjustment impossible and the bearing will fail in a short time. Typically if broken, they broke in shipping or from improper assembly at the factory and we would of course replace the motor under warranty.

[Alma Knack]

Thank you Roger.
The mounting magnets are separated by 1/8” acrylic (my overflow and not my glass). Is it possible there is too much magnetic force disrupting the magnetic shaft and causing the wobbly and failed starts? I believe the magnets are made for 2/3” glass.

I was thinking of going to the plastic store today and buying 2” diameter acrylic discs maybe 3/8” thick to separate the magnets and reduce the magnetic field on the shaft. Do you think that could help?

[rvitko]

This could be a cause, in general less than 1/4" is likely to be problematic. I would check the bearing support though.

[Alma Knack]

I added 1/4” acrylic. So now there is 1/4 + 1/8” separating the magnets. Since the change
it has started about 5 times without wobbling or LEDs illuminating. Thanks for your help.

[rvitko]

Great news!

[Alma Knack]

Do you think any permanent damage could have occurred with all of the wobbly starts?

[rvitko]

No, some bearing damage is possible but this would be visible.