A leak was observed and determined to be within the quintuplet between the two separators.
Upon leak checking the leak was confirmed and found to be at the case gasket of the horizontal slits.
New "viton" o-ring (-178) was ordered and replaced the old buna o-ring.
Part #: TR-202301098
Slits wiped with ethanol, dried and installed. Sytem tested for leak and no leak! Leak rate: about 3E-9 torr.lit/sec.