Gree CN851W1000, Руководство по обслуживанию

Страница: 123 / 233

118
DC Inverter Multi
VRF Service Manual
5.9.2 Pressure maintaining and leak hunting of the system(with refrigerant piping in connection with indoor unit and
outdoor unit)
When refrigerant piping is to be installed, pressure maintaining and leak hunting is required for the piping. After
refrigerant piping is in connection with indoor unit and outdoor unit, pressure maintaining and leak hunting is also
required. The purpose of the test is to check whether any leak is existent at threaded connection of indoor unit and outdoor
unit and at new welded points.
Steps:
Nitrogen is charged to reach 2.5MPa and remains at the pressure for 24h (nitrogen shall be filled from refrigerant
filling nozzles at the big valve as well as the small valve using a pressure gauge; during pressure maintaining after nitrogen
is charged, the pressure gauge shall not be dismantled.)
Observe whether pressure changes in 24 hours. (for eligibility criteria, see pressure maintaining and leak hunting
of refrigerant piping in 5.5.2)
If any leakage, please check threaded connections and new welded spots of indoor unit and outdoor unit. Repair
welding shall be performed immediately. Afterwards, pressure maintaining is repeated until eligibility is reached.
5.9.3 Cautions
a. The pressure meter range of R410A system should be more than 4.5MPa.
b. Record the pressure, ambient temperature and testing hours.
c. Pressure modification: when the temperature changes for 1 1
, the pressure will change for 0.01MPa.
d. The pressure should be stable.
e. If it is necessary to retain the pressure, the pressure should be decreased to 0.5MPa or below. The long-time high
pressure may lead to leak of soldering spot, which may cause safety problem.
f. Before completion of airtight test for refrigerant pipe, do not wrap the soldering spot or horn mouth connecting
spot. During pressurizing, pressurize the outdoor side pipe at the same time instead of pressurizing only one side pipe.
Note: Before completion of airtight test for refrigerant pipe, do not wrap the soldering spot.
5�10 Heat Preservation of Refrigerant Piping
5.10.1 Connection of thermal insulation pipe
Carry out thermal insulation to the refrigerant pipe after confirming that it has no leakage.
Please perform thermal insulation to the refrigerant pipe according to the steps below:
Check if the thermal insulation pipe has met the thickness requirements. If not, the condensing water is easy to
attach on thermal insulation pipe and finally drips. The thickness requirements are shown below:
Refrigerant Pipe (mm) (Outer Dia. x Thickness) Thickness of Thermal Insulation Materials (mm
Φ6.35×0.5 ≥10
Φ9.52×0.71 ≥10
Φ12.7×1 ≥15
Φ15.9×1 ≥15
Φ19.05×1 ≥15
Φ22.2×1.5 ≥20
Φ25.4×1.5 ≥20
Φ28.6×1.5 ≥20
Φ34.9×1.5 ≥20
Wrap the refrigerant pipe according to required thickness. The clearance between thermal insulation pipes shall be
sealed with self-adhesive sticker.