I have an 8 months old Delonghi ecp3420 that one day decided to stop working properly. Instead of producing nice crema, the espresso comes out lukewarm and flavorless. Also, when running the machine without the coffee basket, water is trickling down very slowly - much more slowly than before. I also compared with videos I found online of the machine, so I know what to expect, more or less.
- Using fine grind or more coarse grind does not make a difference.
- Descaling did not help (I tried to descale a few times using both vinegar and that expensive descaler fluid Delonghi sell).
- Cleaning did not help. I cleaned every piece of this machine using descaler fluid.
- Debugging this further, I found out that stretching the valve spring helps. When I do that, water seems to be flowing normally and the espresso comes out great.
However - after I run the machine a few times, it goes back to not working properly: water is slowly dripping, and the espresso comes out flavorless. Stretching the spring again helps for a while.
What am I doing wrong? Stretching the spring every week doesn't seem like a good solution to me. Could it be related to the pump, after all? I would appreciate any advice you may have.