Rancilio silvia thermostat issues

[Rancilio101]

My Rancilio Silvia is about 18yo. What's been happening lately is that after a pull a shot of espresso it does not shut off and continues to drip. The steam occasionally also appears and the water is very hot. It does not happen every time. Then there is an audible click, and at that point I know that I can turn on the steam switch and froth the milk. Sometimes I have to turn the machine off, and only after awhile I would hear the click and know that the boiler is off. So far I have replaced both thermostats and replaced the steam switch (on the advice of technician from one of the coffee machine outlets). I would appreciate any advice in this regard.

 

[shadow745]

A few things to mention... a bit of water dripping after an extraction would likely be caused by a clogged 3-way solenoid. It serves a purpose of diverting pressure into the drip tray and if not functioning 100% it can cause dripping, loss of pressure during an extraction, etc. Do you detergent backflush at all?
As far as steam appearing/water being hot could be a few things. One, a stock Silvia will superheat the water as designed to do and if running water right after the thermostat clicks the element off it will flash boil a few seconds. That's the main reason temp surfing was utilized as many people were getting too hot/bitter extractions. Also could be improper thermostats used when replaced as in the built-in setpoint might be a bit off. Most any single boiler will have a brew and steam thermostat for those that reading this might not be aware of.

 

[Rancilio101]

Thank you for taking the time to write. Your advice is instructive.