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20.2. Adding Refrigerant - Multi-Zone
Systems
The outdoor unit is factory-charged with refrigerant.
Calculate the additional refrigerant required according to the
length of the liquid pipe (one way) between the outdoor unit
and indoor unit connections.
Be sure to add the proper amount of additional refrigerant.
Failure to do so may result in reduced performance.
NOTE:
Interconnecting pipe work between outdoor and
indoor units must be 10 ft. or longer.
NOTE:
Do not remove refrigerant for line lengths less
than 25 ft. R-410A is a blended refrigerant. If you
must remove charge, it is necessary to remove
the entire charge and weigh in the new charge.
Table 1. Adding Refrigerant
System
Pre-charge
Pipe Length
Amount of Refrigerant to add
Two-port
50 ft. (15 m)
0.16 oz ((L1 ft + L2 ft) - 50 ft)
0.005 kg ((L1 m + L2 m) - 15 m)
Three-
port
75 ft. (23 m)
0.16 oz ((L1 ft + L2 ft + L3 ft) - 75
ft) 0.005 kg ((L1 m + L2 m + L3
m) - 23 m)
Four-port
100 ft. (30 m)
0.16 oz ((L1 ft + L2 ft + L3 ft + L4
ft) - 100 ft) 0.005 kg ((L1 m + L2
m + L3 m + L4 m) - 30 m)
Five-port
125 ft. (38 m)
0.16 oz ((L1 ft + L2 ft + L3 ft + L4
ft + L5 ft) - 125 ft) 0.005 kg ((L1
m + L2 m + L3 m + L4 m + L5 m)
- 38 m)
