S1 vivaldi brew boiler question mains dual boiler

[louisxiv]

I have just bought a second hand Vivaldi S1, I worked of a fashion but the water wouldn't dose....so
I decided to strip it down and refurb. After shearing off the drain plug to the steam boiler i found the machine had obviously come from a very hard water area, and upon further inspection had been severely neglected. I don't think it had been cleaned for years (if ever)
/i have cleaned and replaced where needed and am ready to start over.
My question is:
When starting you can hold the buttons to get water through the brew head to fill the boiler but the hole to the group is not at the top of the boiler so once water starts to flow through this hole into the grouphead and through the solenoid won't i end up with a large volume of air trapped in the headspace of the brew boiler? Is this correct. I could open up the screw on the top of the boiler to bleed air out but that doesn't seem to be mentioned anywhere.
As this is a mains fed machine I have about 3 bar of mains water pressure at the boiler I believe.

I suppose it works but it would seem to be more temp stable with the boiler full and more mass of water. Advice please, I'm used to E61 machines so this is all new.
Phil

[chas]

No need to bleed the air. Just run it.