Ok, here is where things stand. In retrospect, the necessity of completely removing the collar should have been obvious. sorry about that. Once off, there was still difficulty in detaching the pump. By gentle wiggling I was able to open up a small crack and then was able to pry them apart. From the photo you can see the obvious scale/corrosion. In particular, I wanted to point out the small hole at the bottom of the motor part of the housing surrounding the shaft. It looks pretty regular, so I'm hoping it's supposed to be there and is not pitting.
I then turned the S1 back on and the motor shaft started to spin as if trying to fill up the group. I did not know if it would stop and whether running dry in this fashion might be bad for it. So I turned it back off and have therefore not tested its responsiveness to the switch. But the motor shaft turns completely freely by hand.
The pump, on the other hand, only turns with considerable difficulty; I have to place a large screwdriver in the notch and twist hard. So I'm guessing a replacement pump is the first thing that needs to happen. Anything to be gained from soaking the pump in a descale solution?
Thanks for all your help in stepping me through this. And the internal pictures on the website are incredibly useful for someone diving into this.
![DSCF1078.JPG](./download/file.php?id=656&sid=a6fbeb40650bb40f9748e1d514ba9875)
- DSCF1078.JPG (75.06 KiB) Viewed 25026 times