Correct, although my notes say closed at 1psi diff or flow through valve of more than 30/lbs of air a minute. This is the valve that will be electrically driven open for smoke clearance mode. Next time you hear the noise stop, have a quick glance on the overhead panel and see what the diff press reading is on the pressurisation panel.
On ground this is the exit for the equip cooling exhaust. When it closes in flight that warmish equip cooling air is directed to the forward cargo compartment to keep the dogs and cats from turning into popsicles.
