Intermitant problem with Tunze 6105

Punchanello · Dec 31, 2018

Hi,

On occasion my Tunze 6105 will stop responding to the controller. I can see the impellor turn 90 degrees ocassionaly but won't actually kick on. Then, after an hour or so it will start working again.

This started after I cleaned the unit in vinegar. Is tgere somerging i am missing? Also, can I check that the plastic side of the bushing and attenuation disk faces the back of the pump?

Punchanello · Jan 1, 2019

I also just noticed that one of my 6105 pumps has the impeller shaft attached to the rear housing of the pump. The other one doesn't. Is this an issue?

Wiskey · Jan 1, 2019

Yeah. It’s supposed to be stuck in there, I had the same issue and got a new motor housing from Roger, the US tunze rep. In my case I was under warrentee but even if not he can sell you the part.

Whiskey

Punchanello · Jan 1, 2019

Wiskey said:
Yeah. It’s supposed to be stuck in there, I had the same issue and got a new motor housing from Roger, the US tunze rep. In my case I was under warrentee but even if not he can sell you the part.

Whiskey

Hi whiskey. The woerd thing is that the shaft is locked tight inside the impeller assembly. Like it is designed that way. It's not loose. I wonder if this is just case od a design change?

Punchanello · Jan 2, 2019

Looks like you were right Whiskey. It is indeed supposed to attach to the back housing. I managed to wriggle the shaft free of the impeller assembly and it's rusted inside.

Super disappointed.

rvitko · Jan 2, 2019

Pumps made from 2008-2012 have a different removable shaft that has a blue bushing on either end and spans from the front cover to the back housing, new pumps have a fixed shaft that is not removable. Shafts made from 2008-2010 were 316Ti and shafts made since were titanium. The 316ti can corrode where covered, the photo is not clear enough to determine what is the issue, it could be just stained calcium deposits (GFO dust combined with calcium). In all cases, the impeller spins on the shaft and they should not be stuck together, the disk is installed so the blue rubber faces down and the slotted face of the black plastic faces up to the bottom of the impeller magnet. The shaft on the older ones is replaceable, part 6065.709, though I would typically replace the entire assembly if it is more than 5 years old, you will usually see some performance increase. 6105.700 is for the old removable shaft design, 6105.701 is for the fixed shaft design.

Punchanello · Jan 2, 2019

Thanks for the response Rvitko. I think I have the new pump without the blue bushing on the end. In any case I bought it 18 months ago. I'll hit it with some vinegar and see if the rust coloured stuff comes off.

Can you tell me whether the shaft can be pushed back in to the rear housing or is it broken? I tried and it seems to sit snugly but I'm not sure if it is intended to be this way.

rvitko · Jan 3, 2019

It should fit solidly in the pump, it is not designed to be removed. If it fits firmly I would add a drop of super glue to the base of the shaft after cleaning and drying the shaft and the seat, then tap it in. If this shaft has a knurled base that has teeth like a gear, it will be fully seated when the top of the shaft is about 1-2mm below the top of the impeller well. I would use a small nut driver so you can drive it in below the top of the well. Newer pumps the shaft seats deeper and it is longer and also has a smooth base. This kind of pump the hole for the shaft is drilled all the way through so their is a hole in the back of the pump. This is basically the same process but the shaft sticks up above the well by about 1-2mm and the shaft stops about 1mm before it would exit the hole in the back.

Wiskey · Jan 6, 2019

When I contacted Tunze they immediately replaced the housing, I was told that this shaft is never supposed to come loose, and if it does there is no way to fix it. I'm not sure how long the warranty is, but at 18 months I would contact Roger and see.

Whiskey