This doesn't address the root cause but a solution
It's definitely not an out-of-round condition. I've always been the only user, and I handle this machine with kid gloves. Today I sanded the hose end again but it didn't really help, so I went after the hose end of the PN wand with a rattail file, then four progressively finer grades of sandpaper, testing the fit frequently. As of this evening it couples and uncouples like new. I'm a very happy camper again.
The bigger question is why this happened at all. I never noticed the problem being worse in dry or damp, cold or warm weather. However, just now I did some research and found that some plastic resins are hygroscopic (see below URL for full article):
Nylon, ABS, Acrylic, Polyurethane, Polycarbonate, PET, PBT
These plastics:
- Have a strong affinity to attract moisture
- Will absorb moisture onto their molecular structure if exposed to ambient air
- Internal moisture can not be removed with hot air alone
If the hose end and/or plastic wand insert are made of one or more of the above, that explains it. The problem got worse and worse with time, which seems consistent with the above statements.
Dysonman1, you may want to have a go on your Mieles. Of course this doesn't address the fact that this problem never should've gotten out of R&D.
Joel
https://www.ptonline.com/knowledgec...n-types/hygroscopic-vs-non-hygroscopic-resins