Ok i will tell you why you need the BLEED switch ON eventhough you have not replied to my post #3
When the bleeds switches are ON,it energizes relays in the ACAU(air con Accessory unit) to PROTECT the Bleed air system during engine start opearations such as over pressure in the bleed air interstage manifold and over temperature.
You have these protections when the switches are where they are supposed to be,in the ON position.
If you need to do a bleeds OFF take off,configure following the SUPP Procedures.
Safe flight.