What was found
AFTER DEPARTURE, RT (NR2) "PRESSURE LOW" CAS MESSAGE POSTED WHILE CLIMBING THROUGH FL200. HYD SYNOPTIC PAGE SHOWED PRESSURE DROPPING TO O PSI WITHIN 1 MINUTE AND 0 PERCENT QUANTITY FOR NR 2 HYD SYS. CREW DECLARED EMERGENCY AND ACFT WAS DIVERTED AND HAD AN UNEVENTFUL LANDING AND TAXI. VISUAL INSP OF NR2 HYD SYS REVEALED THAT LEAK EMANATED FROM O-RINGS LOCATED IN THE DIFFERENTIAL PRESSURE INDICATOR. O-RINGS WERE REPLACED, SYS TESTED WITH NO FURTHER DEFECTS NOTED.