For several months we have had no intentional inleakage or outflow of gas from
our recirculating system. During this period the negative pressure in this system,
as indicated on the console meter, has remained steady at minus 20 inches of water,
despite considerable changes in temperature and other conditions of operation.
I feel some insecurity in this situation. Perhaps, however, it is perfectly
satisfactory and as it should be.
Nevertheless, it might be advisable to check a few points which come to mind.
Basically, what we need to know is whether or not the gas volume really has
remained constant; whether there may have been inleakage (or other accumulation)
not indicated by the meter, and how sensitive the meter is to changes which might