1-11 cabin alt warning

[Ant1981]

I've been getting the alt warning light and horn coming on, but I can't see anything obvious that I haven't followed, any ideas?

[Jon.M]

Hi Ant,

Have you closed the 'Safety Valve' next to the Cabin pressurisation dial on the bottom right of the 2D panel?

That's caught me out a few times. It has a horn warning.

Another warning light comes on if you don't set the de-icing below 10°. But there's no horn if I remember rightly.

Jon

[Ant1981]

T'was the switch on the lower right, thanks

[Ant1981]

All of a sudden, this is happening again! But with the valve closed! Any ideas?

[WhisperJet]

Are you pressurizing the cabin?
Set to 2000ft before T/O and then adjust...

However I don't know if that's a reason...

Nick