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Indoor Unit Located Below Outdoor Unit
Nominal Btu/h
per refrigerant
circuit
Equivalent length up to 25’
Equivalent length 26’ to 50’
Size inches O.D.
Size inches O.D.
Suction(1)
Liquid
Hot gas
reheat(4)
Suction(1)
Liquid
Hot gas
reheat(4)
42,000
5/8 - 5/8
3/8
1/2
3/4 - 3/4
3/8
1/2
48,000
5/8 - 5/8
3/8
1/2
3/4 - 5/8
1/2
5/8
60,000
3/4 - 3/4
1/2
5/8
3/4 - 3/4
1/2
5/8
72,000
3/4 - 3/4
1/2
5/8
7/8 - 3/4
1/2
5/8
84,000
7/8 - 3/4
1/2
5/8
1-1/8 - 3/4
1/2
3/4
96,000
7/8 - 7/8
1/2
5/8
1-1/8 - 7/8
5/8
3/4
120,000
1-1/8 - 1-1/8
5/8
5/8
1-1/8 - 1-1/8
5/8
3/4
150,000
1-1/8 - 1-1/8
5/8
3/4
1-1/8 - 1-1/8
5/8
7/8
180,000
1-3/8 - 1-3/8
3/4
3/4
1-3/8 - 1-1/8
5/8
7/8
220,000
1-3/8 - 1-3/8
3/4
7/8
1-3/8 - 1-3/8
3/4
1-1/8
250,000
1-3/8 - 1-3/8
7/8
7/8
1-3/8 - 1-3/8
7/8
1-1/8
300,000
1-3/8 - 1-3/8
7/8
7/8
1-5/8 - 1-3/8
7/8
1-1/8
350,000
1-5/8 - 1-5/8
7/8
1-1/8
1-5/8 - 1-5/8
1-1/8
1-1/8
400,000
1-5/8 - 1-5/8
1-1/8
1-1/8
1-5/8 - 1-5/8
1-1/8
1-1/8
Nominal Btu/h
per refrigerant
circuit
Equivalent length 51’ to 75’
Equivalent length 76’ to 100’
Size inches O.D.
Size inches O.D.
Suction(1)
Liquid
Hot gas
reheat(4)
Suction(1)
Liquid
Hot gas
reheat(4)
42,000
3/4 - 3/4
3/8
1/2
7/8 - 3/4
3/8
5/8
48,000
3/4 - 5/8
1/2
5/8
7/8 - 5/8
1/2
5/8
60,000
7/8 - 3/4
1/2
5/8
7/8 - 3/4
1/2
3/4
72,000
7/8 - 3/4
1/2
3/4
7/8 - 3/4
1/2
3/4
84,000
1-1/8 -7/8
5/8
7/8
1-1/8 -7/8
5/8
3/4
96,000
1-1/8 -7/8
5/8
7/8
1-1/8 -7/8
5/8
3/4
120,000
1-1/8 -1-1/8
5/8
7/8
1-1/8 -1-1/8
5/8
7/8
150,000
1-1/8 -1-1/8
3/4
7/8
1-3/8 -1-1/8
3/4
7/8
180,000
1-3/8 -1-3/8
3/4
1-1/8
1-3/8 -1-3/8
3/4
1-1/8
220,000
1-3/8 -1-3/8
3/4
1-1/8
1-5/8 -1-3/8
3/4
1-1/8
250,000
1-3/8 - 1-3/8
3/4
1-1/8
1-3/8 -1-3/8
7/8
1-1/8
300,000
1-5/8 - 1-5/8
7/8
1-1/8
1-5/8 - 1-5/8
7/8
1-1/8
350,000
1-5/8 - 1-5/8
7/8
1-1/8
2-1/8 - 1-5/8
1-1/8
1-1/8
400,000
2-1/8 - 1-5/8
1-1/8
1-1/8
2-1/8 -1-5/8
1-1/8
1-1/8
Table 3a: Lineset Recommended Sizes
(1) Maximum vertical lift = 60 feet with suction riser sized traps every 20 feet on the vertical line starting at the lowest point. First size is
horizontal run; second size is for riser.
(4) Hot gas reheat, if ordered, requires one line per circuit. Pitch hot gas (discharge) lines in direction refrigerant flow - minimum 1/8"
per foot.
Example for dual circuit unit: if total system capacity is 240,000 Btu/h, divide by 2 and use the line sizes for 120,000 Btu/h for each
circuit. Follow industry standard refrigeration recommendations for piping. Suction (Vapor) and hot gas reheat lines must be insulated.
RC/FC Series Installation, Operation, and Maintenance Manual