Originally Posted by
WITCHWAY550
As I see from your comments that the 604 and the 601 have the same design for the collector tank. If you know is there an associated EICAS message for low fuel in the collector tank(s)? As I know the Gulfstream 5 and 550 have such a warning. Now how would someone know which collector tank is "low"? I don't know.
According to documentation on the 605 the collector tanks are considered to be a part of their respective main tank and have no independent fuel quantity sensing, indicating, or alerting. It seems likely that the 604 is similar.
ref -
https://www.smartcockpit.com/docs/CL605-FUEL_SYSTEM.pdf