035-15406-002-A-0504
8
Unitary Products Group
NOTE: Add the operating charge of the condensing unit, the evaporator coil and
the refrigerant lines to determine the total refrigerant charge of the system.
1
Charges are based on 40
°
F (5
°
C) suction temperature and a 105
°
F (40
°
C) liquid temperature.
2
Type “L” copper tubing.
Unit Size
(MBH)
Refrigerant
Flow Rate
3
(lbs. / kg. per min.)
Type L
Copper Tubing
(in. / mm O.D.)
Refrigerant Gas
Velocity
(ft. / m per min.)
Friction Loss
4,5
(PSI/100 Ft.)
(kPa / 30.5m)
090
22.5 / 10.2
1-1/8 / 28.5
1-3/8 / 35.0
1-5/8 / 41.3
2450 / 745
1680 / 511
1140 / 346
4.3
1.6
0.7
30
11
5
120
30.0 / 13.6
1-1/8 / 28.5
1-3/8 / 35.0
1-5/8 / 41.3
3500 / 1064
2280 / 693
1560 / 474
8.0
2.8
1.2
56
20
8
1
All horizontal suction lines should be pitched at least 1 inch (25mm) every 20 feet (6m) in the direction of the refrigerant flow to aid the return of oil to the compressor.
2
Every vertical suction riser greater than 3 feet (1m) in height should have a “P” trap at the bottom to facilitate the return of oil to the compressor. Use short radius fittings for these traps.
3
Based on Refrigerant-22 at the nominal capacity of the condensing unit, a suction temperature of 40
°
F (5
°
C) and a liquid temperature of 105
°
F (40
°
C).
4
Although suction lines should be sized for a friction loss equivalent to a 2
°
F (1.1
°
C) change in saturation temperature (or approximately 3 psi [21 kPa]), sizing the lines for the proper return
of oil is more important.
5
These friction losses do not include any allowances for valves or fittings.
TABLE 4 - SUCTION LINES
1,2
Unit Size
(MBH)
Refrigerant
Flow Rate
1
(lbs. / kg. per min.)
Type L
Copper Tubing
(in. / mm O.D.)
Refrigerant Gas
Velocity
(ft. / m per min.)
Pressure Drop
3
Friction
2
Vertical Rise
(PSI/100 Ft.) (kPa / 30.5m)
(PSI/Ft.)
kPa / .3m)
090
22.5 / 10.2
1/2 / 12.7
5/8 / 15.8
300 / 91
190 / 58
11.0
3.5
77
24
0.5
3.5
120
30.0 / 13.6
5/8 / 15.8
3/4 / 19.0
250 / 76
170 / 52
5.8
2.3
40
16
0.5
3.5
1
Based on Refrigerant-22 at the nominal capacity of the condensing unit, a liquid temperature of 105
°
F (40
°
C) and a suction temperature of 40
°
F (5
°
C).
2
These friction losses do not include any allowances for a strainer, filter-drier, solenoid valve, isolation valve or fittings.
3
The total pressure drop of the liquid line for both friction and vertical rise must not exceed 40 PSI (278 kPa). If the pressure drop exceeds 40 PSI (278 kPa), the liquid refrigerant could flash
before it reaches the expansion valve. This flashing will not only cause erratic valve operation and poor system performance, but could also damage the expansion valve.
TABLE 5 - LIQUID LINES
Refrigerant
Circuit
Outside Diameter
(in. / mm.)
Line Charge
(lbs. / ft. - kg / m)
Liquid Line
2
1/2 / 13
.070 / .032
5/8 / 16
.113 / .051
3/4 / 19
.167 / .076
Suction Line
2
1-1/8 / 29
.009 - .004
1-3/8 / 35
.013 - .006
1-5/8 / 41
.019 - .007
TABLE 6 - REFRIGERANT-22 LINE CHARGE
1