Carrier 19XL - 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)