looking at the schematic: DSC 21-30-20- ABN Operation:
BLOWER/EXTRACT FAULT ALERT
When either pb is set at the OVRD position:
The system is in closed-circuit configuration and adds air from the AIR CONDITIONING System to the ventilation air
As mentioned by Mr BH; in conjunction with a DC ESS BUS FAULT, leading to the closure of the AIR COND INLET VALVE (Other inop systems), a computer over heat may develop.
Last edited by Feather44; 23rd November 2015 at 22:52.