Repair of leaky 3-way valve

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Joined: Mon Jan 14, 2008 1:01 pm
Location: Chicago 'burbs

Repair of leaky 3-way valve

Post by caf4brains » Tue May 31, 2016 1:29 pm

My Mini was leaking water from the group after brewing a shot. After repeated detergent flushes intended to dissolve any coffee "stuff" (I usually do a detergent flush once a month - my routine for many years) failed to fix the problem I took the valve apart and took a few pictures to document the process. This is quite easy to do.
  • Unplug the machine
    Remove the cup warmer tray
    Loosen the sides
    Unscrew the front control panel assembly
    Remove the 3-way valve vent piping
    Unscrew the stainless steel 3-way valve from the solenoid (it is not necessary to remove the electrical connection to the solenoid
    Unscrew the 3-way valve from the housing that attaches to the group
    Remove the 4 cap screws that attach the housing to the group
I was expecting to see some scale particles but was surprised to see only a thin film on the valve plug and seat. I gave the wetted parts a hot detergent scrub, rinsed and reassembled it. I worked like a charm. It would only need a small passage for air to backflow from the vent tube to the group which would allow water to drain but I didn't see any obvious culprit.

Attached are some photos showing the process and the parts.
overview.jpg (728.36 KiB) Viewed 3422 times
Housing that attaches to the group
20160528_130348.jpg (88.72 KiB) Viewed 3422 times
3-way valve disassembled
20160528_125452.jpg (80.33 KiB) Viewed 3422 times
View of housing before removal
20160528_125543.jpg (56.39 KiB) Viewed 3422 times

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