Tunze 6055 - Broken?

[Shard]

I recently purchased two Tunze Nanostream 6055 units.

One unit, runs constantly when attached to a power supply. The other, only runs for a few seconds, then stops for a while, then runs for a few seconds again, over and over. It does this no matter which power supply it is connected to.

Is this unit broken? Do these pumps have some kind of internal timer that gets set somehow? Just casually counting the cycle on the intermittent pump, it stays on for 2-3 seconds, then off for 12-14, then on 2-3, repeating.

I have no experience with these pumps previously, and the instruction manual did not say anything about it, so I am hoping someone else will have an idea.

Thanks,
Landon

 

[rvitko]

Hi Landon,

First is it connected at present to a controller?

I would start with no controller.

With the controller out of the picture, if this happens there are 4 possible causes.

1) There is some vaseline in the pump used in a dry test run, too much will act almost like glue. Check this, if you see a big glob under the propeller assembly use a Q-tip to swab it out.

2) The prop is loose on the magnet, if the propeller can free spin when you hold the impeller magnet in your hand, the magnet can turn without engaging the propeller.

3) The prop assembly fits too tight on the metal shaft and cannot turn freely, try the one from your working pump as a test.

4) The motor has a defect but this is very, very rare, the 6055 is really so reliable I almost never have returns, in a whole year I maybe see a dozen come back for repair and at least 8 are a bad power supply or one of the problems listed above. Of the remaining four, the most common problems are a shaft that is pulled out or a broken cable, but the motor is still usually electrically good.

 

[Shard]

Hi rvitko,

Thanks for responding.

To answer the first question, there is no controller used on it for this to happen, just the pump, so this happens sans any control device. I tried
your suggestions above.

1) Did not appear to be gunked up, but I cleaned the prop assembly barrel well. A little gunk in the bottom, but not really much. Problem still occurred.

2+3) The prop catches the magnet within a half turn or so, so it does not spin freely. I also tried the other prop assembly and it did not help. The same situation still happens.

4) Maybe this is a very, very rare case? I tried both power supplies, and the pump still behaves the same way, where as both power supplies work on the other pump. The shaft appears to be firm in the pump, so I don't think it would be this. The cable appears to be in good condition, so unfortunately it would appear this is narrowed down to the pump? Due to the almost cyclic nature of the on/off cycle, my guess is that it must be something with the electronic control mechanism in the pump unit itself?

Thanks again,
Landon

 

[rvitko]

Are these new units or bought used? I would send it in for repair/replacement, I just need the pump. In the case of a bad cord, they typically outwardly look fine, but there are five very fine wires inside, think of something just a bit beefier than an ethernet cable, one good kink or tug can break a wire inside, usually in this case moving the cord in certain positions will get it working but of course that isn t a fix, just a diagnostic.

Tunze USA
305 Victor St
Austin, TX 78753

 

[Shard]

Bought from another reefer (used). Being a graduate student (by default poor), new is sometimes a foreign concept to me They are however in really good condition, that is why I am baffled by this situation.

But you are right, it could be a break in the smaller wires inside. I assume something along the lines of 24awg braided is used, so extensive movement can sever the lines. However, the cyclic pattern displayed does not seem indicative of a short. If capacitors are used in the pump housing this could be a charge/discharge kind of situation.

 

[rvitko]

Usually if it is a pump problem it is an internal short from heating, something where a transistor is shorting against a heat sink or the board due to expansion, send it in, bottom line is to fix it we probably have to replace the motor.

 

[Shard]

And what is the projected cost of the replacement?

 

[rvitko]

Worst case scenario it is around $115, but it may be warranty, we just need to check what is going on.