38MARB: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
16
REFRIGERANT LINES
General Refrigerant Line Sizing
1. The outdoor units are shipped with a full charge of R410A refrigerant. All charges, line sizing, and capacities are based on runs of 25ft. (7.6 m). For runs
over 25 ft. (7.6 m), consult the long-line applications section for the proper charge adjustments.
2. The minimum refrigerant line length between the indoor and outdoor units is 10 ft. (3 m).
3. Refrigerant lines should not be buried in the ground. If it is necessary to bury the lines, not more than 36 in (914 mm) should be buried. Provide a
minimum 6in (152 mm) vertical rise to the service valves to prevent refrigerant migration.
4. Both lines must be insulated. Use a minimum of 1/2in. (12.7 mm) thick insulation. Closed-cell insulation is recommended in all long-line applications.
5. Special consideration should be given to isolating interconnecting tubing from the building structure. Isolate the tubing so vibration or noise is not
transmitted into the structure.
IMPORTANT: Both refrigerant lines must be insulated separately.
Table 9 displays the following maximum lengths allowed.
Table 9 — Piping and Refrigerant Information for Cooling Only and Heat Pump Systems
• The charge amount listed in Table 9 is for piping runs up to 25 ft. (7.6 m).
• For piping runs greater than 25 ft. (7.6 m), add refrigerant up to the
allowable length as specified in Table 10.
Long Line Applications,:
1. No change in line sizing is required.
2. Add refrigerant per Table 10.
Table 10 — Additional Charge
System Size
12K
6K
9K
12K
18K
24K
30K
36K
(115V)
(208/230V) (208/230V) (208/230V) (208/230V) (208/230V) (208/230V) (208/230V)
Min. Piping Length
ft. (m)
9.8 (3)
9.8 (3)
9.8 (3)
9.8 (3)
9.8 (3)
9.8 (3)
9.8 (3)
9.8 (3)
Standard Piping Length
ft. (m)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
Max. outdoor-indoor
height difference
(OU higher than IU)
ft. (m)
32.8 (10)
32.8 (10)
32.8 (10)
32.8 (10)
65.6 (20)
82 (25)
82 (25)
98.4 (30)
Max. outdoor-indoor
height difference
(IU higher than OU)
ft. (m)
32.8 (10)
32.8 (10)
32.8 (10)
32.8 (10)
65.6 (20)
82 (25)
82 (25)
98.4 (30)
Max. Piping Length with no
additional refrigerant charge
per System
ft. (m)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
24.6 (7.5)
Total Maximum Piping
Length per system
ft. (m)
82 (25)
82 (25)
82 (25)
82 (25)
98.4 (30)
164 (50)
164 (50)
213 (65)
Additional refrigerant charge Oz/ft
(g/m)
0.161(15)
0.161(15)
0.161(15)
0.161(15)
0.161(15)
0.322(30)
0.322(30)
0.322(30)
Suction Pipe
(size - connection type)
In (mm)
ø1/2” (12.7) ø3/8” (9.52) ø3/8” (9.52) ø1/2” (12.7) ø1/2” (12.7) ø5/8” (15.9) ø5/8” (15.9) ø5/8” (15.9)
Liquid Pipe
(size - connection type)
In (mm)
ø1/4” (6.35) ø1/4” (6.35) ø1/4” (6.35) ø1/4” (6.35) ø1/4” (6.35) ø3/8” (9.52) ø3/8” (9.52) ø3/8” (9.52)
Refrigerant Type
Type
R410A
R410A
R410A
R410A
R410A
R410A
R410A
R410A
Charge Amount
lb. (kg)
2.47(1.12)
2.38(1.08)
2.6(1.18)
2.6(1.18)
4.08(1.85)
5.73(2.6)
6.06(2.75)
7.5(3.4)
UNIT
SIZE
TOTAL LINE
LENGTH FT (M)
ADDITIONAL CHARGE, OZ/FT. FT (M)
MIN
MAX
10-25
(3-8)
>25-82
(8-25)
>82-98
(25-30)
>98-213
(30-65)
6
10 (3)
82 (25)
None
0.16
9
12
18
98 (30)
0.16
24
164 (50)
0.32
30
36
213 (65)
