Service manual

SERVICING
45
• The vertical difference between the condenser and
evaporator when the evaporator is below the con-
denser can approach 150 feet, as long as the equiva-
lent length does not exceed 150 feet.
• The distance between the condenser and evaporator in
a completely horizontal installation in which the indoor
and outdoor unit do not differ more than 10 feet in
vertical distance from each other can approach 150
feet, as long as the equivalent length does not exceed
150 feet.
4. Two-Stage Condensing Unit: The maximum length of
tubing must not exceed 75 feet here indoor coil is located
above the outdoor unit.
NOTE: When the outdoor unit is located above the
indoor coil, the maximum vertical rise
must not exceed
25 feet. If the maximum vertical rise exceeds 25 feet,
premature compressor failure will occur due to inad-
equate oil return.
5. TXV Requirement: All line set applications over 50 ft will
require a TXV.
6. Vibration and Noise: In long line applications, refriger-
ant tubing is highly prone to transmit noise and vibration
to the structure it is fastened to. Use adequate vibration-
isolating hardware when mounting line set to adjacent
structure.
Most refrigerant tubing kits are supplied with 3/8"-thick
insulation on the vapor line. For long line installations over
50 feet, especially if the line set passes through a high
ambient temperature, ½”-thick suction line insulation is
recommended to reduce loss of capacity. The liquid line
should be insulated if passing through an area of 120°F or
greater. Do not attach the liquid line to any non-insulated
portion of the suction line
Table 8 lists multiplier values to recalculate system-
cooling capacity as a function of a system’s equivalent
line length (as calculated from the suction line) and the
selected suction tube size. Table 2 lists the equivalent
length gained from adding bends to the suction line.
Properly size the suction line to minimize capacity
loss.
Cond
Unit
Tons Suct Liq Suct Liq Suct Liq
1 1/2 5/8 1/4 3/4 3/8 3/4 3/8
2 5/81/43/43/83/43/8
2 1/2 3/4 3/8 3/4* 3/8 7/8 3/8
3 3/4 3/8 3/4** 3/8 7/8** 3/8
3 1/2 3/4 3/8 7/8** 3/8 1 1/8 3/8
4 7/8 3/8 1 1/8 3/8 1 1/8 3/8
5 7/8 3/8 1 1/8 3/8 1 1/8 3/8
Line Diameter (In. OD)
REFRIGERANT LINE LENGTH (Ft)
0-24 25-49 50-74***
*7/8" required for full ratings
**1 1/8" required for full ratings
***Lines greater than 74 feet in length or vertical elevation changes more than 50 feet, refer to the long
line set.
TABLE 8. CAPACITY MULTIPLIERS AS A FUNCTION OF
SUCTION LINE SIZE & EQUIVALENT LENGTH
50 75 100 125 150
18,000 3/4
.99 .97 .96 .95 .95
24,000 3/4
1 .99 .99 .98 .97
30,000 3/4
.98 .97 .96 .95 .94
3/4
.93 .90 .86 .83 .79
7/8
.98 .96 .94 .92 .90
3/4
.93 .90 .87 .83 .80
7/8
.97 .96 .94 .93 .92
1-1/8
1 1 .99 .99 .98
3/4
.90 .86 .82 .78 N/R
7/8
.96 .94 .93 .91 .89
1-1/8
1 1 .99 .99 .98
7/8
.93 .91 .89 .86 .84
1-1/8
.99 .98 .98 .97 .97
36,000
42,000
48,000
60,000
Nominal
capacity
Btuh
Vapor line
diameter
(in.)
EQUIVALENT LINE LENGTH (FT)
Table 8
NOTE: For a condenser with a liquid valve tube connection
less than 3/8" diameter, use 3/8" liquid line tubing for a
line set greater than 25 feet.
TABLE 9. LOSSES FROM SUCTION LINE ELBOWS
(EQUIVALENT LENGTH, FT.)
3/4 7/8 1-1/8
90° short radius 1.7 2 2.3
90° lon
g
radius 1.5 1.7 1.6
45° 0.7 0.8 1
I.D. (in.)
Type of elbow fitting
Table 9