Refrigerant piping is important in particular. Refrigeration cycle of the split air conditioner is realized by the perfect
piping work.
Piping Length And Elevation
If the piping is too long, both the capacity and reliability of unit will drop. As the number of bends increase, resistance to flow
of refrigerant system increases, thus lowering cooling capacity and as a result the compressor may become defective. Always
choose the shortest path and follow the recommendation as tabulated below:
Model (VCU)
Maximum length, m (ft)
Max. elevation, m (ft), (50Hz)
Max. elevation, m (ft), (60Hz)
Max. number of bends
Liquid pipe size
Gas pipe size (50Hz)
Gas pipe size (60Hz)
Piping Connection
•
Do not use contaminated or damaged copper tubing. If any piping, evaporator or condenser had been exposed or had been
opened for 15 seconds or more, then vacuum and purge with field supplied refrigerant. Generally, do not remove plastic
rubber plugs and brass nuts from the valves, fittings, tubing and coils until it is ready to connect suction or liquid line into
valves or fittings.
•
If any brazing work is required, ensure that nitrogen gas is passed through coil and joints while the brazing work is being
done. This will eliminate soot formation on the inside wall of copper tubings.
•
Cut the pipe stages by stages, advancing the blade of pipe cutter slowly. Extra force and a deep cut will cause more
distortion of pipe and therefore extra burr.
•
Remove burrs from cut edges of pipes with a remover. This will avoid unevenness on the flare face which will cause gas
leak.
•
Remove bypass tube from the unit. Service valves are closed from the factory and ready for brazing.
•
Use quenching cloth for brazing operation at the service valves. This is to prevent damage to the unit and service valves.
•
Align the center of the piping and sufficiently fit to the service valves. Braze the connections using industry accepted
methods and materials.
•
Be sure to execute heat insulation. (polyurethane form with thickness more than 15 mm)
•
Except the outdoor unit, which is pre-charge with refrigerant R-22, the indoor unit and the refrigerant connection pipes
must be purged because the air that contain moisture remaining in the refrigerant cycle may cause malfunction to the
compressor.
Additional Charge
The refrigerant is pre-charge in the outdoor unit, but additional charge of refrigerant after vacuuming is necessary. Follow the
recommendation as tabulated below:
Model
25A(50Hz)/
VCU
25A(60Hz)
L <= 5m
0.100 kg
L = 7m
0.176 kg
L = 10m
0.290 kg
L = 15m
0.480 kg
L = 20m
-
REFRIGERANT PIPING WORK
25A
30A
15 (0.6)
35 (1.4)
8 (0.3)
10 (0.4)
8 (0.3)
10 (0.4)
10
10
3/8"
3/8"
5/8"
5/8"
5/8"
5/8"
30A(50Hz)/
35A(50Hz)/
30A(60Hz)
35A(50Hz)
0.400 kg
-
0.600 kg
0.100 kg
0.650 kg
0.250 kg
0.900 kg
0.500 kg
1.150 kg
0.750 kg
1-4
35A
40A
35 (1.4)
35 (1.4)
10 (0.4)
10 (0.4)
10 (0.4)
20 (0.8)
10
10
3/8"
3/8"
3/4"
3/4"
3/4"
7/8"
40A(50Hz)
50A(50Hz)
-
-
0.100 kg
0.100 kg
0.250 kg
0.250 kg
0.500 kg
0.500 kg
0.750 kg
0.750 kg
50A
60A
35 (1.4)
35 (1.4)
10 (0.4)
20 (0.8)
20 (0.8)
20 (0.8)
10
10
3/8"
1/2"
3/4"
7/8"
7/8"
7/8"
60A(50Hz)/
40/50/60A(60Hz)
-
0.100 kg
0.250 kg
0.500 kg
0.750 kg