Jura Impressa F7: Coffee not hot enough

Hello everyone,

My Jura Impressa F7 basically works really well. However, the coffee is not really hot, even though the temperature is set to "high". I've already descaled the machine a few times, but I can't find any limescale lumps or similar in the descaling solution, so I assume that the actual limescale present is quite small and dissolves completely. Theoretically, however, there could be quite a lot of limescale in the machine, the machine didn't have a happy childhood ;-) I suspect the problem is more in the sensors or control system. Speaks temperature sensor and/or thermostat. However, I have no experience of such faults... What is your recommendation?

Thank you!

What kind of descaler are you using?
Of course, this could also be due to the temperature sensor. The only thing that helps is to try another one.
How quickly does the coffee flow?

I use this one:

https://maxxi-clean.com/Entkalker-Universal-fluessig-mit-Farbindikator-750-ml

The coffee flow seems "normal" to me ....

Descaler is ok. It contains 10-15% amidosulfonic acid.
Have you measured the outlet temperature with a thermometer?

I just measured the temperature at the sink. At the beginning I have 80 degrees, but then the temp goes down to below 60 degrees!

Hello everyone, does anyone have any comparative values?

I have a Z5.
The temperature is relatively constant at around 75°C
What kind of F7 is it? An old one with the touch or the newer model?

If you have a multimeter, you could measure whether voltage is present at the heater and when it starts to be present again when coffee is drawn.
You just have to be careful, 230V alternating current!

Thanks for the info. Yes, I will check when the supply voltage is applied. It's an Impressa F7:

https://www.kaffeevollautomaten.org/kaffeemaschinen/jura/1059_impressa_f7/

So with hot water only, hot water comes out at 90 degrees C. The heating is almost permanently on, it only switches off two or three times for 0.5 seconds. So everything is ok, right? But why is the coffee not really hot?

Finished coffee (180ml) has only 66 degrees...

How is the heating controlled when coffee is drawn? In the same way as for hot water?

This is the same channel. Behind the heater, water is distributed to the hot water nozzle and to the brewing unit (there is a valve directly after the distributor) via a Y-distributor. So the water comes from the same heater...

I'm just wondering how the coffee valve is controlled at all. It seems to be a purely mechanical pressure valve. Presumably it switches on at higher pressure.

The hot water valve works via a manual rotary switch.