Gree GMV-PD100W/NAB-K, Service Manual

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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:
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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.
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, 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
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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
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Refrigerant Pipe (mm) (Outer Dia. x Thickness) Thickness of Thermal Insulation Materials (mm
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Wrap the refrigerant pipe according to required thickness. The clearance between thermal insulation