However, back pressure doesn't explain the fact that it's bubbling in fridge, but not in the Hall. The gas is flowing into the system, but is not flowing out where it's supposed to ==> there is a leak.
It's probably worth checking the gas connections in the shed with some Snoop -- maybe there's a leaking connection there that the temperature changes are aggravating.
Next access we should try the following:
1) Squirt some Snoop at any gas fitting joints in the Hall, and
2) (if no culprit is found), try to increase the inflow rate at the
fridge in the shed while monitoring the flow rate down at the chambers.
Jack's offered to give us a hand with this.
AFAIK, Xin has not noted any problems with the chamber
performance, but having the flow through the chamber vary by factors of
30 seems an unnecessary risk.
A copy of this log entry has been emailed to: kalyan, xqian, segal