A320 Ventilation
 

ECAM procedure VENT BLOWER FAULT says if you have a DC ESS BUS FAULT along with VENT BLOWER FAULT , the crew should LAND ASAP. What has DC ESS BUS got to do with the Ventilation blower fan? As per FCOM the blower is powered by AC1 and DC1.

It might be something to do with the avionics air conditioning valve being inop with a DC ESS BUS fault combined with a blower fault. Not sure though.

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.

Thank you for your time. That solves my question.:)

Also with DC ESS bus fault , extract fan is inop.