Gerardo M., Janos Cs.

After the aLog of Dave (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=79442), we came onsite and found that the instrument air supply is not operational. In the reservoir tank the pressure was still ~80 psi, but the device 'as it is' was not operational; so the solenoid valve wasn't open to the system, and in general the whole system was off - which explains Dave's aLog 79442. When we arrived on site, GV6, GV7, and GV8 were already soft-closed.
The following actions have been taken:
- The instrument air supply was isolated from the instrument air system
- A compressed air cylinder was hooked up to the system in the mechanical room (see picture), and we were slowly ramping up the air pressure, and so all the GVs opened up
- GV7 was intentionally soft-closed after this, to prevent any undesirable X-manifold pressure raise, if GV7 decides to close
- The X-manifold turbo was switched on, and after its pressure went below the pressure in the manifold, it was valved in. Now it is holding the X-manifoild's pressure at 3-4E-8 Torr. It will remain like this until the pumpdown (upside of the whole story that we will have the X-manifold turbo as an additional firepower during pumpdown)

Other considerations:
- As the instrument air system consumes the air very fast (from 1500 psi to 1000 in half an hour - note here that it opened all the GVs, so it won't be this bad all along), GV6 and GV8 can close before morning
- To mitigate this potential issue, Nitrogen or compressed air cylinders will be hooked up to GV6 and GV8 directly, to minimize the losses (especially, if the air supply cannot be fixed quickly)
- After the GVs soft closed in the beginning of this whole story, the pressures in the beamtube and in the CPs didn't change drastically, they followed the typical daily pressure cycles