We've had a devil of a time getting V1 to open, due to the Interlock code.
The short story is that if C1:Vac-PTP1_pressure > 1.0, the interlock code won't let you push the button to open V1 (but it won't close V1).
PTP1 is broken, so the interlock was frustrating us. It's been broken for a while, but this hasn't bitten us till now.
We tried swapping out the controller for PTP1 with one of Bob's from the Bake lab, but it didn't work.
It said "NO COMM" in the C1:Vac-PTP1_status, so I figured it wouldn't update if we just used tdswrite to change C1:Vac-PTP1_pressure to 0.0. This actually worked, and V1 is now open. This is a temporary fix.