comments and questions about revised Nano Streams...

[flipteg]

last year, i bought 2 Nano Streams 6025's... i was disappointed when the impeller kept wearing itself down rubbing against the bottom of the shaft... Roger replaced them but after trying a total of 6 Nano Streams, all with the same problems, i decided to wait for the revised Nano Streams...

i finally got the revised Nano Streams July and i kept my fingers crossed for the first few weeks it was in operation hoping the impeller wearing down problem is finally fixed... the pair that i have have been in operation for 4 months now and i am happy to report that the bottom of the impeller still looks new... also, just a couple of days ago, one of the pumps started acting funny and it would not start up properlly... upon inspection, the inside was coated with calcium carbonate... but even still, none of the parts was worn out... a couple of hours soak in vinegar and the pump is as good as new... in the case of calcium carbonate build up, i would rather have the pumps stop working rather than continue to work until it wore itself apart...

but i have one question though, on the first version, there was no stainless steel washer on the bottom of the shaft... the plastic at the bottom of the shaft and the bottom of the impeller wore out so quickly... but in the new version, even though there is a stainless steel washer at the bottom of the shaft, the bottom of the impeller is still plastic... what i don't understand is, why doesn't the plastic impeller wear out...? when my pump stopped working, the stainless steel washer had so much calcium carbonate buildup that it looked so bumpy... and yet, the plastic bottom of the impeller that rubs against it still looks new...

in any case, i've been very happy with Tunze's customer service and after a year of buying the pumps, i'm finally very satisfied with them...

 

[rvitko]

We added the stainless steel disk because it is actually the plastic that wears out the plastic. The plastic is reinforced with glass fiber and the fibers act like sand paper and grind down the parts. We are working toward changing the plastic but it is not as easy as it sounds, every plastic creates a different pitch of noise and different volume so we are still testing this but we are close to a design which will not need the stainless steel disk.

 

[flipteg]

thanks for the reply...

so you're saying that the bottom of the impeller and the plastic washer that was used initially are made from the same plastic that contains fiber and that causes both the impeller and the bottom of the shaft to grind each other...?

 

[rvitko]

It causes the bottom of the drive unit to wear the disk- part 6025.74, the stainless steel disk prevents this.