Slowly opened GV1 and then GV2 to combine the vertex with YBM and XBM volumes. Accidentally burped in dry purge air from GV1 gate annulus because outer o-ring leaks (when vertex was vented) and this caused YBM turbo to trip and YBM pressure to rise to e-5 Torr. YBM turbo is now spun down and scroll off; vertex turbo is pumping the entire corner station, backed by scroll. Shut down QDP80 and flushed header with purge air.