I heat the reservoir with an air fryer at 250 degrees for six minutes, after which I immediately attach the portafilter and fill from a boiling kettle. My food thermometer shows the water temp leveling off at 200 degrees just prior to inserting the pressure gauge/plunger.

I use the Flair for travel and i heat water with a collapsible travel kettle,
so the KISS principle rules for me. This is my pre-heating pyramid:

Pour water over:

Cylinder
---------inserted-into-----------------
Portafilter wihout dispersion screen
---------into----------------------------
Portfilter cover with stainless steel
screw, head on the inside.

I let them spend a minute together while I grind with the Knock Aergrind.

For some reason if I preheat the piston I get leaks, wonder if the rubber becomes too soft.

PS: New Flair user, I went cheap with an Illy Iperespresso 3.2 and Capsulone metal refillables, never ever again:(

Recently I also steam preheat piston, but no leaks on mine

Also switched to steam pre heat and not looking back. A lot faster, hotter and can leave it unattended while preparing portafilter.

I sandwich the cylinder in an 3cup Bialetti with its screen/rubber removed

Sorry for this thread bump ...

I don't have my flair pro yet, but can someone update this thread with the diameter of the flair pro brew cylinder? Or, the diameter of the "steaming" device that has worked best for you, be it a moka pot or cezve? Cezve seems like best option given the handle, although moka pots from tjmaxx, marshalls, homegoods, etc are cheap and readily available.

Thanks