USB Nano Air Pumps deaths, teardown, and (apparent) fix

[Guppy Guy]

I am considering using one on my outdoor guppy pond this year, but I am not sure if it will handle 110 degrees F, on top of high humidity. Any suggestions?

Before you say that the temp is too high for guppies, I know. I am planning on putting a few broad leaved plants over the tank, and possibly having an old pc fan(I’ve got tons 😉) blowing over the surface.

[MarkM]

I know that if I was left in the sun in 110 degree heat with high humidity, I'd be dead within 15 minutes tops. Cory's post mentioned that leaving it out in the sun all summer killed one of his, so I'd say avoid that.  If you're already planning on using a cooling fan for the water, getting cooling to the pump wouldn't hurt.  

As an update to mine, they both gave up the ghost again and no amount of smacking is bringing them back.  There also isn't any more chewed up plastic inside.  Both motors sound super crunchy when manually spinning. 

With eatyourpea's success I'm torn between seeing if they can be salvaged again and taking them fully apart.  I'm also looking for somewhere to source the RF-370CA-12560 hobby motor, but so far haven't found a price point where it makes sense. 

 

[CT_]

I actually considered replacing them with a brushless motor which would last way longer, but as you say, at the price point a brushless motor is really more expensive than a traditional air pump even.

[Guppy Guy]

On 2/24/2022 at 10:06 PM, MarkM said:

I know that if I was left in the sun in 110 degree heat with high humidity, I'd be dead within 15 minutes tops. Cory's post mentioned that leaving it out in the sun all summer killed one of his, so I'd say avoid that.  If you're already planning on using a cooling fan for the water, getting cooling to the pump wouldn't hurt.  

As an update to mine, they both gave up the ghost again and no amount of smacking is bringing them back.  There also isn't any more chewed up plastic inside.  Both motors sound super crunchy when manually spinning. 

With eatyourpea's success I'm torn between seeing if they can be salvaged again and taking them fully apart.  I'm also looking for somewhere to source the RF-370CA-12560 hobby motor, but so far haven't found a price point where it makes sense. 

 

I think I will put a traditional air pump inside the house, and run the line outside. 

For a replacement motor, have you checked digikey?

[CT_]

You probably won't find the exact part number.  From what I've found they're made to order in quantity for OEMs so its probably only possible to find the whole assembly, ie a new pump.  fun fact: multiples of basically this same pump (slightly different) are in every kureg machine.

[MarkM]

It's been a while but I finally got around to trying these pumps again.  I tried to save them with silicon grease, but..

After reflecting over the past few months, I find I still have a use for the Nano pumps.  I love the new coop pumps and am using 3 of those for my primary tanks (and will convert the rest as the old tetra whisper pumps die off), but it's really hard to beat how dead silent these Nano pumps are.  Even if I have to purchase a new Nano pump every 6 months it would be worth it for the tank sitting right next to me in my office.

At this point I tore them apart more out of general academic inquiry than for anything else.  Reminder, I am just a hobbyist and not a professional.  These were disassembled with a Dremel and hammer in my garage, not meticulously in a lab setting.  I can say both units showed similar amounts of wear, but I won't be drawing any conclusions from what I found.  It would just be assumptions and I am as likely wrong to be wrong as I would to be right. Now onto the carnage.

 

I didn't take a picture, but the plastic on the shaft is not glued on.  If you are scavenging parts from a dead motor, it's easily removed with pliers.

  Here you can see the telltale signs from the magic blue smoke escaping. The shiny gouges are from dremeling off the retention points from the housing. 

 

Here you can see how the brushes contact to commutator.  The commutator seemed really torn up and the housing was filthy.  The dust looks like its a combination of the commutator,  brushes, and the permanent magnet.  

Here you can see the collection of residue on the back plate.  They way I had these mounted (hanging by the c clip) this would have been up, which makes me believe the uh "percussive maintenance" and disassembly knocked this crud everywhere.  

This picture really shows how chewed up the commutator was.  (ignore damage to the shaft itself, that was from me. )

In this terrible picture of the housing you can see the stator magnets and there is some slight wear. 

 

Like I said, this was mostly to satisfy my curiosity than to pinpoint a cause.  My takeaways from this thread are more about air pumps in general.

• Check your stones more often than you think you should.
• Don't ask too much from your air pumps.  Move them as high up as you can to preserve longevity.
• Check your check valves (avoid them if you can) as they can clog up too.
• Beware of back pressure and pump strain.

To the last point when I want to reduce flow rather than just restricting the line, I've taken to bleeding off some of the airflow.  Not sure if this is causing other problems, but it seems to be less stressful on the pump (less noise and heat, but I don't have any hard numbers).  I accomplished this with a splitter and a printed screw clamp, but you might be able to get finer control from something like Ziss Air Valve. 

[CT_]

Great photos!

I took mine apart and one of the brushes was down to 1 finger of 3 so I figured that was my problem.  Frankly its impressive these last as long as they do.  motors like this are usually only rated for a couple hundred hours.  IDK how these survive so long.

 

One thing I do is cut the resistor off when I get them.  It halves the power consumption, and therefore the heat.  And since I don't use a battery pack with them it doesn't cause any problems either.  I can't say if lower heat lengthens the life but it does for most things mechanical and electrical.

 

On 3/28/2022 at 11:30 PM, MarkM said:

To the last point when I want to reduce flow rather than just restricting the line, I've taken to bleeding off some of the airflow. 

I started to do this too.  more load = more current = more arcing on the brushes = more wear.  They also stall more easily at high load. 

 

 

[BF McUmber]

On my work tank, I had a pump die on me as well after a few months of use. I could tap it and it would start again for a few minutes before stopping. The CO-OP took care of me and got me a new one. Since I work with some nerdy people they wanted to take it apart. When they did they saw that the plastic was also shredded where the plastic meets the metal pin. They cleaned it off but it did not help in this case. 

The setup I had it on was a 10 gallon so it had about 25" of air tube, a ZISS needle valve, and a ZISS air stone. Initially when it stopped bubbling it was still shaking, so we thought it may be a clog. We opened the needle valve and also loosened the air stone to hopefully open things up. In our simple experiment we were thinking the needle valve was doing a lot more constricting on the pump flow than the air stone was. The air stone in this situation was not terribly old though.   

The pumps fit really conveniently where I want to use them, so now I just hold on to a couple extra in case one dies. 

[nabokovfan87]

On 1/21/2022 at 6:45 AM, Naidu said:

Are you running a check valve? I wonder if check valve is causing back pressure making the metal shaft to work harder and shred plastic.

Definitely interesting.

In general, yes this is a very interesting design issue.  As someone who has designed stuff with plastics with specifically wear in mind, I would wonder what the thickness / materials of everything is in your stress locations in the design.  I am pretty sure you can basically remove all design faults with some material or tolerance changes.

[kahjtheundedicated]

Adding my experience to this, I just had mine get to the "starts working again if you hit it" phase after 4 months of use. Hanging on the rim of a 10 gallon, no check valve, and adjusting flow/pressure with a valve attached to a T, bleeding off excess to atmosphere. Upon disassembly, I also found some nylon shavings, and no indication of lubricant of any kind. But the off-center hole not yet significantly enlarged or disformed.

I cleaned out the shavings and applied some teflon lubricant to the offset hole and shaft. It now starts up without percussive maintenance and is now working at a significantly higher rpm.

I will now use it as a backup air source rather than primary, and periodically monitor it. If the wear continues and becomes progressively problematic, I may experiment with making a bushing for it.

Also, has anyone opened up the new co-op air pump yet? Would like to know its construction and possible longevity issues or the possibility of maintenance and repair. I know the co-op is good about replacing faulty units, and disassembly voids any kind of warranty. But personally I would always rather repair a device than replace it.

[nabokovfan87]

On 8/29/2022 at 9:41 AM, kahjtheundedicated said:

Also, has anyone opened up the new co-op air pump yet? Would like to know its construction and possible longevity issues or the possibility of maintenance and repair. I know the co-op is good about replacing faulty units, and disassembly voids any kind of warranty. But personally I would always rather repair a device than replace it.

Bentley has a good video on it.

[Matt B]

I found myself linked to this thread after reading about the many pros and cons of these pumps. I really like them and have had great experiences with them!   So while having some morning coffee,  I was suddenly inspired to tear into one of my old noisy ones,  just to take a look.  This is not a CO-OP pump, but rather another brand...No way I'm I  going to be able to reassemble this one, but I sure learned a lot taking it apart!