R410a DC Inverter 60Hz Carrier service manual
128 Installation
copper pipe 1/4"
copper pipe fittings
copper pipe
nitrogen gas cylinder
hign pressure flexible pipe
decompress valvevalve
nitrogen charging connecting fitting
brazing weld part
oxygen nitrogen
6. Highlight
1) Control the nitrogen pressure to be about 0.2-0.3kgf/cm² during the welding.
2) Ensure the gas is nitrogen; oxygen will easily leads explosion, so it is forbidden.
3) Use pressure reducing valve, and control the pressure of the charged nitrogen to be about 0.2kg/ cm².
4) Select a proper position for charging nitrogen.
5) Ensure that the nitrogen passes through the welding spots.
6) If the pipeline between the position for charging nitrogen and the welding spot is rather long, ensure
that the nitrogen is charged for sufficient time so as to discharge all the air from the welding spot.
7) After completing the welding, charge the nitrogen continuously until the pipe cools down completely.
8) Try best to conduct welding downwards or horizontally and avoid face-down welding.
7. Cautions
1) Take fire-prevention measures when conducting welding (ensure that a fire extinguisher is available
beside the operating position).
2) Avoid getting burnt.
3) Pay attention to the fit gap of the position where the pipe is inserted.
Note: The follow table shows the relation between the minimum embedded depth and gap at the copper
pipe joint.
Type
Outer Diameter of
Pipe (D) (mm)
Minimum Inlaid
Depth (B) (mm)
Gap A—D (mm)
A
D
B
brazing welding
side
5<D<8 6
0. 05—0. 21
8<D<12 7
12<D<16 8
0. 05—0. 27
16<D<25 10
25<D<35 12
0. 05—0. 35
35<D<45 14
3.1.5 Pipe cleaning out
3.1.5.1 Flushing copper pipe
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