You can avoid drilling the bypass valve by adding an external regulated bypass circut to your pump. {image}

For some time I am tuning my rebuilt second hand Rancilio S26 espresso machine. I have already done several mods including boiler isolation, digital boiler pressure control, PIDed grouphead, Arduino time and volume controlled preinfusion and extraction. I have been considering several approaches to ...

@Carneiro and Eric: Do you have any updates on your projects with MGFR pump and motor? I am willing to buy one and control it with Arduino - the brain of my heavily modified Rancilio S26. The other option is to buy R/C brushless low kv outrunner motor with speed controller and attach it to a normal ...

@ duke-one: It's Norgren 33d pressure switch. For 30$ you can buy a 30PSI pressure transducer with 0,5-4,5v output on ebay. 20$ for an Arduino, 5$ for a power supply, 10$ for 25A SSR and 5$ for project box and wires. There is a free PID library (software) available for Arduino online. Total cost of ...

It's doable, easier and more fun than installing thermocouple. All you need is pressure transducer, PID accepting its signal and a SSR. You can find digital pressurestat as well. Moreover you can play with an Arduino {image} I have bought mine Norgren digital pressurestat on Ebay for 65$ (new), howe...

Shake your grinder vigorously and use the vacuum cleaner