Hi Natstrackalpha,
What does the Ram Air do when switch is selected to open Ram Air Valve (please . . don`t say open the valve . . )
Allows ram air to flow through the pack inter cooler ducting into the cabin (without going through the pack).
What is the Ram Air for?
Conditioning the cabin when de-pressurised and no pack operation.
[I thought it was for air inlet in the event of a pack failure, total pack failure.]
Correct or deliberate turn off of packs.
I also thought it was for fast smoke removal (in case somebody had burnt the dinner in the galley . . .etc)
Faster smoke removal using pack on high flow - but if smoke is coming from both packs then it is an alternative method.
Does/will having the Ram Air . . . open / letting in air, affect or do anything to the Cabin pressure significantly/
Oh Yes! (Thanks Churchill) Zero delta pressure.