Carrier PC211 Start-Up, Operation And Maintenance Instructions Manual page 158

Calculate Maximum Load
To calculate maximum load points, use design load condition data. If the machine full load
cooler temperature difference is more than 15° F (8.3 C), estimate the refrigerant suction and
condensing temperatures at this difference. Use the proper saturated pressure and temperature
for the particular refrigerant used.
Suction Temperature:
42 F (5.6 C) = 71.5 psig (521 kPa) saturated refrigerant pressure (HCFC-22)
Condensing Temperature:
98 F (36.7 C) = 190 psig (1310 kPa) saturated refrigerant pressure (HCFC-22)
Maximum Load T2:
54 – 44 = 10° F (12.2 – 6.7 = 5.5° C)
Maximum Load P2:
190 – 71.5 = 118.5 psid (1310 – 521 = 789 kPad)
To avoid unnecessary surge prevention, add about 10 psid (70 kPad) to P2 from these
conditions:
T2 = 10° F (5.5° C)
P2 = 130 psid (900 kPad)