Nextion display was separated from its PCB and mounted with a 3D printed adapter on the front panel.

A custom PCB was made to accommodate the front panel controls. It's based on nRF52840 module.

Mounted on the back side of the panel.

Everything is connected.

Button and LED PCB covers are covered with adhesive aluminum tape to dissipate heat from the boiler.

Final result.

Sirena is getting a standard Gaggia Classic aluminum boiler.

However, two adapters need to be made to mount it in place of the old one.

The top cover needs two cutouts to accommodate boiler terminals that otherwise won't fit.

The boiler is placed as low as possible but not touching the body.

Gaggiuino uses a transducer for pressure measurements, so it must also be accommodated.

All connections are made with overwrapped silicone tube with Oetiker clamps, standard for Saeco machines.

Since the tray is shallow, the 3-way valve exhaust was silenced with a Breville exhaust box.

Steam coil is connected in series with a second 3-way valve between the coil and the main boiler. The second valve exhaust is going into the exhaust box.

PCB v2 was used for the project.

SSR for the main boiler was placed on the bottom plate.

Most of the wiring was reused from the original one.

Remove the coil and connect top of the boiler directly to the steam valve.

Also if the specific fitting for the boiler top outlet is unavailable, the regular GC steam valve might fit with some fiddling. I'd use a cardan joint (it's half BMW here after all) to get the knob connected.