Carrier 38VMH-1P Service Manual page 9

:
Case 4
• Bends in piping cause pressure loss during transportation of refrigerant, so fewer bends increases performance.
• The equivalent length of each bend is 1.64 feet.
• The equivalent length of each Y-Joint or header is 1.64 feet.
• Total "downstream indoor capacity" is the total capacity of all the indoor units connected downstream.
• The pipe length difference from the first branch to each indoor unit must not exceed 49 feet.
Item
Total piping length
Maximum distance from ODU to farthest IDU
First branch to farthest IDU
Height between ODU and IDU (ODU above IDU)
Height between ODU and IDU (ODU below IDU)
Height between IDU and IDU
Height between first branch and IDU
Model
38VMB036HDS3-1
38VMB048HDS3-1
38VMB060HDS3-1
* When the length of "L1" > 230 feet, the gas pipe should be increased from 5/8" to 3/4" or from 3/4" to 7/8". The pipe adapter must be
located as close as possible to the outdoor unit.
Downstream Indoor Capacity (KBtu/h)
Capacity ≤ 15K
15K < Capacity ≤ 78K
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Fig. 17 —Piping Design (Case 4)
Table 13 —Piping Length
Piping in the Figure
L1 + L3 + L4 + L5 + L6 + A + B + C + D + E + F + G + H
L1 + L4 + A, L1 + L4 + B, L1 + L4 + C, L1 + L4 + D, L1 +
L3 + L6 + E, L1 + L3 + L6 + F
L1 + L3 + L5 + G, L1 + L3 + L5 + H
L4 + A, L4 + B, L4 + C, L4 + D, L3 + L6 + E, L3 + L6 + F,
L3 + L5 + G, L3 + L5 + H
H
H'
h1
h2
Table 14 —Selection of "L1"
Gas Pipe
5/8 *
3/4 *
Table 15 —Selection of L3~5, A~F
9
Maximum Length
492
296
131
164
131
49
49
Liquid Pipe
3/8
Gas Pipe
1/2
5/8
A210232
Equivalent Length
-
328
-
-
-
-
-
Liquid Pipe
1/4
3/8