What was found
PRESSURIZATION SYS NOT FUNCTIONING PROPERLY. COULD NOT GET MORE THAN 6.0 PSID, 9600FT CABIN ALT AND SLOWLY CLIMBING AT FL330. DECENDED TO FL270, DIFFERENTIAL REDUCED TO 5.0 PSI CARGO HEAT VALVE CLOSED FULL TIME AT 10,000FT, CABIN ALT= 5500, DIFFERENTIAL 1.8 PSID, SLOW INCREASE. PERFORMED CABIN PRESSURE LEAKAGE TEST IAW MM 05-51-101-2. DECAY RATE WELL WITHIN LIMITS. R & R CABIN PRESSURE CONTROLLER & CABIN PRESSURE CONTROL PANEL AS A PRECAUTION IAW MM 21-31-010-4 & OPS CHECKED NORMAL IAW 21-31-000-2.