Tunze 1073.05 Pump problem

[Tremor_Clown]

Hi Roger,

I purchased a Tunze 1073.05 Pump to use as my return back on 3/15/12 from Marine Depot.
The pump was great until just a few months ago when I noticed that the red flow control knob didn't really do much and water was coming out slow.
For the time I ended up just turning the red flow control knob to full/100% and was satisfied with the average flow. It was definitely not anywhere near as fast as it was during the first 6 - 8 months of use.
Earlier today I came home to find the Tunze 1073.05 return pump stopped running. I unplugged it, plugged it back in and nothing. I even moved the red flow control knob and still nothing. I pulled the pump out to inspect the unit and noticed that the impeller has some form of rust like deterioration inside the middle of the impeller (I attached some pictures).
I cleaned the pump and now suddenly the Tunze 1073.05 turns on but is running extremely slow...even at 100% on the red flow control knob.

Is this something electrical with the flow control box or is it the impeller?
Please advise what I can do to fix this.

Thanks,
Ryan

 

[rvitko]

I don't see anything unusual with the drive unit. Here are the possibilities that come to mind.

1) Binding in the bearings, on each end is a ceramic bearing in a silicon sleeve, these seat in sockets at the base of the motor and on the impeller housing. Make sure these are fully seated, if they ride higher on the shaft or the shaft or bearing has some calcium deposits, the pump can bind up and will usually run slower due to dragging the bearings and eventually seize altogether. Check that the shaft can spin in these bearings freely, then seat them. I use the wood handle of a small file to seat the one in the base of the pump but a Bic pen can also do the job, you need to press it in.

2) The end connector has the potentiometer and some other control electronics, if this got wet, that may be a cause.

3) Their could be a motor issue, but this would be unusual as I am not familiar with a motor issue where it slows down, they usually work or do not work and perhaps even stop intermittently.

 

[Tremor_Clown]

Hi Roger,

Thank you for the fast response!

Actually to respond to your first point (1), that is actually how I got the pump to start working again. I de-assembled the pump and cleaned out each part with a light vinegar/RODI water solution. Each part was taken out and cleaned - shaft/impeller, the little sleeve on top and bottom and even the pump housing/body. When I put everything back together, the shaft/impeller seems to spin fine.
Before I did that, the pump wouldn't start up and I tried everything.

The end connector flow box (with the red flow switch) hasn't gotten wet.

Besides the pump simply shutting off last night, the issue with the reduced flow has been slowly getting worse over the last few months. Originally I didn't think anything of it since I had the ability to increase the flow on the control box so I just kept upping the flow. Now the flow is at 100% and that is pretty much the only way the pump will move any water. If I turn the red flow switch down to slow the flow, the pump simply stops pushing water (yet you can still hear the pump running and I guess the impeller is spinning).

Since the pump is still under warranty, where do I send it to get it fixed or replaced? I actually need it ASAP as it is my main return pump for my system.

Thank you again,
Ryan

 

[Craig Borowski]

You can send it in to:

Tunze USA
305 Victor Street
Austin, TX 78753

One other thought, any chance your return line to the tank has slowly become clogged over the last couple of months? Of course if you were testing the pump separately that wouldn't be the cause of the problem, but if you've been testing it while plumbed into the system, a clogged return line (which could happen quickly if bio-pellets or other carbon dosing is used) could cause this.

 

[Tremor_Clown]

Hi Craig,

Thank you for the response. Do I need to fill any forms out and attach a copy of my receipt?

I pulled the pump and all the plumbing apart to and found it wasn't bad, except for some slime coating inside the return tubing. Nothing clogged though. I tested the Tunze 1073.05 by itself without the plumbing and I think it is an electronic issue. The red flow control knob only has two options: on and off.
Also, after I soaked the impeller/shaft in a vinegar/water mix, the middle of the impeller/shaft looks noticeably worse than it was a few weeks ago: it has different tints of orange/brown in the middle of the magnet. Honestly it looks like somehow salt got inside the middle and is rusting.

Thanks,
Ryan

 

[rvitko]

If you can include a copy of the receipt and a note with your return address and phone number, that will be all we need.