GCHV CHV Mini Series, Service Manual, Page: 100 / 128

202105 99
CHV Mini VRF 50/60Hz
P
ar
t 3
-In
st
all
at
io
n
Outdoor unit (set)
High pressure liquid pipe
Low pressure gas pipe
Oil return bend
60m
30m
Indoor unit set
3.8 Remove Dirt or Water in the Piping
Make sure there is no any dirt or water before connecting the piping to the outdoor units. Wash the piping with high
pressure nitrogen, never use refrigerant of outdoor unit.
3.9 Airtight Test
(1)After the refrigerant pipe is installed and connected to the indoor unit, and before the connecting pipes between the
indoor and outdoor units are connected to the valves of the outdoor units, refill the nitrogen with the pressure of
40kgf/cm² (4.0MPa) from the gas side and the fluid side simultaneously, mark the pressure value, and then perform 24-
hour air tightnesstest.
(2) If the pressure drops, recheck the leakage of all interfaces and then maintain the pressure for 24 hours.
(3) Don't connect with the outdoor unit during maintaining the pressure.
3.10 Vacuum
(1) The vacuum pump has the vacuum degree of less than -0.1MPa and the air displacement of more than 40L/min.
(2)It is unnecessary to vacuumize the outdoor unit. Don't open the check valves at the gas side and the liquid side of the
outdoor unit.
(3)Make sure the vacuum pump can drop up to -0.1MPa within 2 hours; if it fails to drop up to -0.1MPa after 3 hours,
check moisture or airleak.
(4)The vacuum pump must have a check valve. Make sure there is no any dirt or water before connecting the piping to the
outdoor units. Wash the piping with high pressure nitrogen, never use refrigerant of outdoor unit.