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 »

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 8193 times
Housing that attaches to the group
Housing that attaches to the group
20160528_130348.jpg (88.72 KiB) Viewed 8193 times
3-way valve disassembled
3-way valve disassembled
20160528_125452.jpg (80.33 KiB) Viewed 8193 times
View of housing before removal
View of housing before removal
20160528_125543.jpg (56.39 KiB) Viewed 8193 times
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