DeLonghi Magnifica ESAM3500 brews for too long

Question

My machine is a DeLonghi Magnifica ESAM3500 , though this may apply to other models as well. It all started after I ran a descaling cycle on an otherwise faultless machine.

Symptoms:

• Coffee would drip during the pre-infusion phase of brewing, then stop and continue brewing,
• Too much coffee is brewed to the point of overflowing your cups
• Rinsing cycle at power on/off takes too long and too much water is poured.

Needless to say the coffee tastes like crap.

Answer 1

The solution was to replace the flowmeter (picture is of a different machine but the position of the sensor is the same):

Here is the part in detail:

In my case there was corrosion on the connector that was causing the sensor to malfunction, the chrome-plating on the lower part of the connector (the one that goes into the sensor) was eaten by the corrosion, this is how it looks after cleaning with WD40:

I ended up replacing the whole sensor with a spare that i got from a friend that's into buying used/broken machines and refurbishing them for sale. Otherwise you can get them from ebay by searching for "delonghi esam flow-meter" and making sure what you buy looks exactly like the picture above.

Answer 2

To add to this solution. I had the same issue with it rinsing for far to long and coffee exprressos over filling cups. It was after I fixed up the corrosion on the terminal. The issue was that I put the water connecters on incorrectly so it was not picking up the full flow as the things was probably spinning backwards. Works like a charm now, these machines are so easy to work with.