MCAC-VTSM-2014-04
R410A DC Inverter VRF V4 Plus Individual Series 50Hz
Installation
75
8. Branch pipe installation
The branching pipe must be installed horizontally and error angle of it should not be larger than 10°. Otherwise,
refrigerant assignment will be uneven and malfunction will be caused.
9. Remove dirt or water in the piping
Make sure there is no any dirt or water in the pipe before connecting the piping to the outdoor units.
Wash the piping with high pressure nitrogen, never use refrigerant of the outdoor unit to do that.
10. Airtight test
Connect pipe on hi-pressure side with hi-pressure valve.(For multi-modules parallel connection, please
connect gas balance valves).
Weld the piping on low-pressure side with gauge joint.
Charge nitrogen from hi-pressure valve core to gauge joint.
After airtight test, weld low-pressure ball valve and piping on low-pressure side.
Note:
The air tightness test is conducted by pressurized nitrogen (R22 system: 28kgf/cm
2
, R410A system: 40kgf/cm
2
).
It is not allowed to adopt oxide, flammable gas and toxic gas to conduct air tightness test.
It
’s not allowable to welding low pressure ball valve with low pressure side piping before charge nitrogen.
Wrap the lo-valve and the balance valve by wet cloth for protection when welding..
11. Vacuum with vacuum pump
Do vacuum with vacuum pump instead of refrigerant.
Vacuuming should be done from liquid and gas side simultaneously. The pressure should be lower than
30Pa.
Use the vacuum pump which vacuum level lower than -0.1MPa and the air discharge capacity above
40L/min.
The outdoor unit is not necessary to vacuum, don’t open the outdoor unit gas and liquid pipe shut-off valves.
Make sure the vacuum pump could result as -0.1MPa or below after 2 hours or above operation. If the pump
operated 3 hours or above could not achieve to -0.1MPa or below, please check whether water mix or gas
leak inside of the pipe.
10°
10°
A
Correct
Wrong
U-shaped branching pipe
Horizontal surface
A direction view