If you own Gaggia Classic Pro espresso machine and the water flows very slowly from the group head, then you might have to clean the 3 way solenoid valve. That's exatly what happened to us recently. The whole cleaning process is well documented here: I could just stop here, since the video is sufficient to do the cleaning. However, the video does not show a real world situation since their Gaggia model is already clean. Here is what happened in out kitchen. I used these tools and products: The whole repair took me about 1:15 hour. I opened the case: I located the 3 way solenoid valve and opened it: I used the CLR cleaning product for descaling. I descaled only few parts from the valve to minimze contact with the other parts of the espresso machine. I also used disposable gloves and old plastic bottle for cleaning. At the end I used old tootbrush for removing residual particles. Before and after the cleaning process: I rinsed all cleaned parts several times and then let them dry
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