Cleaning Of Refrigerant Piping - Gree GMV-PD100W/NAB-K Service Manual

DC Inverter Multi
VRF Service Manual
Cooling
o avoid getting a burn in following processes, common wet cloth (humidity content is low, meaning that
there shall not be water drips when welded part is cooled; and because shrinkage factor of copper is different
from that of welding material, too quick cooling that would cause cracking of braze welding shall be avoided)
can be used for cooling welded parts.
The following items shall be checked after welding is completed

5.8 Cleaning of Refrigerant Piping

After a section of pipeline is welded, cleaning of piping is necessary.
Nitrogen pressure is utilized to remove foreign matters (such as dust, water and beryllium oxide caused by
welding) in the piping.
5.8.1 Main purposes of cleaning are as follows
To remove foreign substances and water that may enter the piping due to improper storage and
transport.
To check whether big leakage is existent at connections of the piping between indoor unit and outdoor
unit
5.8.2 Cleaning steps:
a. Mount a pressure gauge on nitrogen cylinder;
Outdoor side
(liquid pipe).
c. All copper pipe ports outside the A side of indoor unit shall be blocked by blanking plugs
d. The valve on nitrogen cylinder shall be opened to maintain pressure at 28Kgf/ cm2
f. Cleaning
The mouth of the pipe shall be blocked with insulation material held by hand until pressure rises to a level
shall be blocked again. Repeat such procedures several times. Afterwards, use a wood board posted with white
paper to check it. If there is not evident dirt on the white paper, the pipe will be considered clean.
g. Shut off the main valve of nitrogen
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Nitrogen bottle
Liquid pipe
Air pipe
Copper pipe
Blanking plug
Copper pipe ports not to be cleaned
shall be blocked by blanking plugs
Indoor unit A Outdoor unit B
The opening of the pipe not to be purged
shall be blocked with blind plug.
Block with
insulation materials
Cleaning process
Quick release