Carrier 38MHRCQ12AA1 - General Refrigerant Line Sizing; Long-Line Applications; Piping and Refrigerant Information

SG-38MHRC-01 Specifications subject to change without notice. 19
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), refer to “Long-Line
Applications”on 19 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 11 lists the maximum lengths allowed.
Table 11 — Piping and Refrigerant Information
Long-Line Applications
1. No change in line sizing is required.
2. Add refrigerant per Table 11.
SYSTEM
SIZE
12K (115 V) 9K(208/230 V) 12K(208/230 V) 18K(208/230 V) 24K(208/230 V)
Piping
Minimum Piping Length ft. (m) 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)
Maximum outdoor-indoor height difference
(OU higher than IU)
ft. (m) 32.8 (10) 32.8 (10) 32.8 (10) 65.6 (20) 82 (25)
Maximum outdoor-indoor height difference
(IU higher than OU)
ft. (m) 32.8 (10) 32.8 (10) 32.8 (10) 65.6 (20) 82 (25)
Maximum Piping Length with no additional
refrigerant charge per System
(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)
Total Maximum Piping Length per system ft. (m) 82 (25) 82 (25) 82 (25) 98.4 (30) 164 (50)
Additional refrigerant charge
(between Standard – Maximum piping
length)
Oz/ft
(g/m)
0.161(15) 0.161(15) 0.161(15) 0.161(15) 0.322(30)
Suction Pipe (size - connection type)
In
(mm)
ø1/2” (12.7) ø3/8” (9.52) ø1/2” (12.7) ø1/2” (12.7) 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) ø3/8” (9.52)
Refrigerant
Refrigerant Type Type R410A R410A R410A R410A R410A
Charge Amount lb. (kg) 1.79(0.81) 1.59(0.72) 1.79(0.81) 2.98(1.35) 3.92(1.78)