If you set a LOWER cruise altitude what does the pressurisation system do?
A lower cruise altitude on the pressure controller, while maintaining flight level.
I don't know the wiring, tell me if you do...
It's speculation, but as the max diff goes from 8,35 psi above FL370 to 7,80 psi below FL370 (I had to look up the numbers) I figured the controller starts aiming for a new, lower, diff pressure if you wind down the cruise altitude on the pressure controller. Normally you'd actually start a descent too.