Tunze 1073.05 suddenly running noisy

[Frogmanx82]

I had an issue where the water level got low and the pump was pulling in air. It still wasn't running right when I fixed the water level so I took it apart and did a thorough cleaning with vinegar. The pump housing and impeller looked pretty clean but when I put it back together it made a tremendous noise. It seemed to be pumping full strength, in fact maybe even more than normal.

It ran dead quiet for a year and a half but I can't figure out what is making it so noisy now. I've taken it apart again and no luck getting it any quieter. This is not a tolerable noise level. I can notice it upstairs from the tank and the sump is in an enclosed cabinet.

To be clear, this is the DC version of the 1073.

 

[rvitko]

At either end of the impeller is a bushing, they look like an orange top hat and have a ceramic sleeve inside that the shaft spins in. Make sure the shaft is not stuck to these bushings and that the bushings are fully seated in the top cover and down in the motor, they should not come out without effort and you need to use a dowel, pen etc, to push the bottom one in.

 

[Frogmanx82]

I'm not sure what else I can do. The white sleeves are solidly in the orange bushings. They are free spinning around the shaft. Everything is clean, which for these shouldn't even be that necessary considering it ran for a year without cleaning and was dead quiet. Am I missing something?

How far into the orange bushing should the white sleeve be pushed? I've tried many positions and it doesn't affect it. Could something else be going on?

Also what part is not supposed to come out easily? That wasn't clear to me.

 

[rvitko]

The bushings should not come out easily, they get pressed into a socket in the impeller cover and down into the motor, you have to press these in before inserting the impeller and you cannot use the impeller to press them in as they just ride up the shaft.

 

[Frogmanx82]

Thanks, that was the problem, I didn't have the bottom bushing pushed firmly into the seat.

I pushed the orange bushing into the bottom with some PVC tubing, turned the pump upside down and was sure it wouldn't fall out. I loaded the spindle with the white sleeve into the bushing with the pump still upside down. Finally I pushed the other bushing into the cap, made sure the other sleeve was on, put on the cap and sealed it up. Works great.

 

[rvitko]

Great news, I generally use a dowel, the butt of a small file or screwdriver or one of those cheap bic pens that are just a white tube with black cap.