Rancilio S20 overfilling while machine is off

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by estwenty »

I started having problems with my Rancilio S20 MIDI, at first I thought it was the water level probe. Water would leak out the anti-depression valve when ever I switched on the machine and I would have to empty a pitcherful of water from the steam wand before I could use it. I changed the probe, drained the boiler and knew the probe was ok since the pump would stop at what seemed like a proper level.

Long story short, this morning I found a puddle around the machine as the tank had overfilled during the night while the machine was off. I'm guessing it's time to change the valve that does the auto-filling? I need advice as to what part to buy.

Am I right to assume this is the part in question? :

this is a closeup of the specs of the solenoid unit:

Would this be a suitable replacement part? :

https://www.espressotec.com/rancilio-cl ... -4675.html

Thanks in advance to anyone who can help.

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#2: Post by stefano65 »

If the autofill is filling up and therefor working it will trigger the pump/motor and you will of course hear them running.

If the machine is filling up per say "slowly" even when power turned off but the water line open
you have possibly sediments preventing the plunger of the solenoid pilot (the mechanical part of the 2-way valve assembly)
to close entirely.
You could also have the water pressure pushing too much on the above mentioned plunger and leaving it partially open (too much water pressure and or an aging solenoid valve).

Or can be electrical if the coil is energized and triggers the plunger to open which is close to impossible to happen with the mahcine turn off,

Possibility one is the most common one.
Stefano Cremonesi
Stefano's Espresso Care
Repairs & sales from Oregon.


#3: Post by az3002 »


#4: Post by az3002 »


#5: Post by az3002 »