Silvia Refurb Project - Pre-Infusion

[Mike Petro]

OK, while I am under the hood inside of Silvia, what hacks have you folks tried to add a pre-infusion function to her?

I was wondering if a timer that when you hit the brew button, caused the pump to run for X number of seconds then stop for Y number of seconds, then run again till the brew switch was turned off would work?

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Mike Petro

[Mike Petro]

OK, after experimenting with my water plumbing I am revising my approach. My plan is to use an "on-delay" timer (the # of seconds to be determined with testing) and then turn the pump on.

My theory is this, my household water pressure is about 2 bar and it will flow through the pump in a static state with the valves open. So I let the water supply solenoid and 3-way valve open but delay the starting of the pump, this will allow water to flow at 2 bar through the portafilter, and hopefully allow the swelling of the puck to minimize channeling etc. I will use a bottomless portafilter and time how long it takes to see a slight seepage at the bottom of the filter basket, this will give me the time value I need to set on the pump delay timer.

Is my theory sound?

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Mike Petro