> the smoke alarm is wired to shut down the CRAC units
Why not just turn the CRAC back on?
> you don’t trust the automation unless there’s a big red-painted, mechanically connected lever you can pull to turn it off
Seems like this is one of those cases where you want to override the automation.
They'd be shutdown by a dry contact that may variously be coming from the VESDA (Very Early Smoke Detection Apparatus), or an internal smoke detector, or a duct mounted smoke detector. Not as simple as flipping an obvious switch on a front panel.