GP Series Portable Chillers Chapter 3: Installation 19 of 64
Refrigerant Charge Determination. The approximate amount of refrigerant charge required
by the system varies based on the total length of the refrigerant lines and the size of the
chiller. Referring to Figure 5, determine the amount of charge based on the horsepower of the
chiller and the amount of charge based on discharge and liquid line sizes and lengths. Add
these three numbers together to find the final operating charge. The final operating charge
must be verified by running the system and checking the liquid line sight glass.
Figure 5: Refrigerant Charge Determination
Condenser and Chiller Charge (per circuit)
Minimum Design Ambient - °F
Chiller
Model 60 50 40 30 20 10 0 -10 -20
GPRC5 9 9 10 11 12 13 13 13 14
GPRC7.5 10 10 12 14 15 16 16 17 17
GPRC10 13 13 15 17 19 20 21 21 22
GPRC15 18 19 22 25 27 29 30 31 32
Line Size
OD (inches) Discharge Line
LBS of R-410a Liquid Line
LBS of R-410a
3/8 0.3 3.2
1/2 0.6 6.0
5/8 1.0 9.6
3/4 1.5 14.4
7/8 2.1 20.0
1-1/8 3.7 34.1
Oil Charge Determination. The remote air-cooled portable chillers are factory charged with
the amount of oil required without field-installed piping. Additional oil required is dependent
on the amount of additional refrigerant added.
Calculate the amount of additional oil required by using the following formula:
Pints of oil (Copeland Ultra 22cc) = lbs of R-410a added for field installed piping / 100.