Our Breville Barista Express BES870BSXL recently stopped building any pressure and only trickled water out of the group head (the steam wand and hot water works fine). I replaced the pump just to be sure. When I applied voltage to the old 3-way solenoid, it doesn't respond at all (no clicks or buzzing), so I replaced it.

After installing, I noticed that the moment I plugged in the machine (not yet powered on), the new 3-way solenoid immediately clicks (and appears to get hot if I leave the machine plugged in). I've confirmed all the wiring is correct - red/blue/green on left-side 2-way solenoid, orange/blue/green on right-side 3-way solenoid. I don't believe it's a faulty 3-way solenoid because when I swap in a new 2-way solenoid to the orange/blue/green wires, it clicks as well.

(To make things even more confusing, my meter shows both the red/blue and orange/blue wires are actually hot when the machine is plugged in, yet the red/blue-wired 2-way solenoid doesn't click, only the orange/blue-wired 3-way does [and if I swap them, whatever is connected to the orange/blue clicks immediately when the machine is plugged in.])