Jura Impressa Ultra, pumpe Kaputt?

Hello coffee friends,

I have an older Jura Impressa Ultra (500er?) which I have repaired over the years.

I have a suspicion this time too, but I certainly don't know yet.

The suffering began with the fact that once again "please cleanse" was required. The only difference is that even after 20 attempts, the dung thing always aborted prematurely before "Insert tablet" came. A little later I took the brewing unit apart and cleaned it manually and simply ignored the message.

Yesterday (of course at the WOE) suddenly only a drop of coffee arrived, the espresso cup was barely half full. The pump had a lot of trouble, but it was quiet.

So again an attempt with the cleaning and after some trying with "Reset Codes" the process required a tablet - and then ran through to the end. Some water was used in the process.

But as soon as the cleaning was done, the machine wanted to decalcify. I was careless as I was, so I also started the decalcification - without letting the machine cool down beforehand. After a long time with occasional, quiet humming, I should empty the cup (there was also plenty of lime water in it) and rinse the rest of the formula. Only it never came to an end. It still hummed occasionally quietly, but the water level in the tank did not become any less.

After more than two and a half hours of still humming senselessly I took the last maybe 100 millilitres out of the water tank. Due to a lack of water, the process was then completed with "Fill container and rinse".

It just didn't flush. Nothing comes from manual rinsing or from the steam pipe.

So I probably washed some coarser chunks of lime somewhere where they don't dissolve and clog up a bit. So once again I disassembled the machine and checked where it spikes. Only I can't find it.

If I remove the pressure hose at the outlet of the diaphragm regulator and blow it in, I can blow it out through both positions of the ceramic valve. So it's not tight. When I disconnect the hose at the inlet of the pump, water bubbles out when the tank is on. So that's it, then. I disassembled the flowmeter - it is clean as a whistle and hums like a top when I blow into it.

I can suck air (but not blow) through the dismounted mambran regulator - and so can the pump. Both are difficult, which I would expect.

An experiment with a dismantled membrane regulator, i.e. only the pump with inflow, should have produced a water fountain from the pump according to my imagination. But not a drop arrived.

So the pump misplaced? Before I disassembled the water supply, the pump noise was quiet - resistance. After the disassembly the hoses were all empty and the pump is loud because it does not suck anything. But that sounds again, as if the pump would actually work.

I have no problem getting a new pump. This is a relatively cheap spare part and I can change the CP3 pump to a CP4 pump on that occasion. But it worries me that I can't solve the problem any other way.

In the pump inflow I would not have suspected such lime quantities that they would ruin the pump. He's actually from the radiator. If there's any misalignment, it's more in the hot water area.

Anybody got any ideas?

Greetings from the alpine country
,smallfreak