Gree R410A Manual page 85

NOTICE! Liquid pipe that is within 20m (65-5/8 feet) doesn't need to be added refrigerant.
Therefore, the minimum quantity of additional refrigerant = (23-20)×0.054+11×0.022=
0.404kg(14oz).
5.3.2 Operation procedure for adding refrigerant
(1) Put the charging tank on the weightometer, record the reading and then calculate the
data after charging refrigerant;
(2) Use charging conduct pipe to connect the double-ended manometer with governing valve
and liquid-charging tank to the detection head of gas valve and liquid valve. Before
connection, please release some refrigerant and then drain out the air inside the charging
conduct pipe.
(3) Confirm that the gas valve and liquid for outdoor unit is at of status.
(4) When the unit hasn't been turned on, open the governing valve for the liquid-charging
tank and then charge refrigerant from gas pipe and liquid pipe at the same time.
(5) Obeserve the data weightometer, close the valve after it is reached to requirement and
then close the valve for liquid-charging tank;
(6) If the refrigerant can't be added completely, add it when turning on the unit. Charge
refrigerant from the detection joint of cooling gas pipe or detection joint of gas vavle.
5.3.3 Notice for filling refrigerant
(1) Calculate the section and length of cooling liquid pipe preciously for the precision
refrigerant-charing volume.
(2) Measure the additional refrigerant volume preciously;
(3) Invert to charge the R410A for ensuting the liquid-charging;
(4) When the temperature is low, heat the liquid-storage tank with hot water or hot
wind for helping refrigerant-charging. However, prohibit use flame to heat the
liquid-storage tank directly. Otherwise, it may cuase personal injury or property
damage due to explosion.
5.4 Airtightness test
5.4.1 Importance of airtightness test
The airtightness of VRF system is the leak tightness of the pipeline for refrigerant,
which the guarantee for safe and reliable operation. The leakage of refrigerant may
affect the operation of air conditioner seriously, or even damage compressor and then
lead to breakdown of system. Therefore, it needs to perform the airtightness test.
If the there's gas leakage after the system is installed completely, because the indoor
celling decoration are all finished, it is will be very difficult to find out the leakage point.
Thus, the airtightness test of the system must be finished before finishing indoor
decoration.
5.4.2 Operation procedure for the airtightness test
(1) Before ex-factory,cut-off valve for gas pipe and liquid pipe of outdoor unit is
turned off, Please confirm that before operation;
(2) Before test please smear a little corresponding lubricant oil at Blanking plug and
pipe terminal, and use two wrenches for fixing blanking plug.
(3) Do not allow to connect the pipeline of outdoor unit for test during airtightness test.
(4) The system test pressure for R410A is 4.15MPa (3.0MPa for R22 refrigerant
system). Nitrogen must be used as the medium for the airtightness test and the nitrogen
should be dry. Increase pressure slowly for three steps:
Photovoltaic Direct-driven VRF
for North America
83