Haier MRV 5-RC VP1-112B Service Manual page 144

<Table-2>
Pipe size
Ø6.35
Ø9.52
Ø12.7
Ø15.88
Ø19.05
Ø22.22
Apply refrigerant oil
Fig.8
<Note>
• Excessive tightening will result in cracking at the flare and refrigerant leakage.
• To weld the refrigerant pipe, please make nitrogen replacement (*1), or send nitrogen (*2) into the refrigerant pipe
while welding the pipe (refer to Fig.10). Finally use the flare or flange to connect the indoor unit and valve box.
(*1) Nitrogen replacement method is provided in the multi-split system work manual.
(*2) If nitrogen flowing and welding proceed simultaneously, do use pressure reducing valve. Approximately 0.02
MPa (0.2 Kg/cm with a slight feeling of breeze) pressure is quite proper.
<Note>
• For pipe welding, do not use antioxidant, for its residue may cause tube blocking and component fault.
• For pipe welding, do not use flux. If the flux is chlorine product, it will corrode the tube; if it contains fluorine, it will
even cause detrimental effects to the refrigerant system, such as refrigerant oil deterioration. Please do not use
phosphor copper for welding material (BCup-2).
Tightening angle
60°~90°
60°~90°
30°~60°
30°~60°
20°~35°
15°~30°
Ø19.05 pipe connected on site
Welding
Accessory pipe
Ø19.05 pipe connected on site
Welding
Binding
Weld
Nitrogen
Refrigerant pipe
Fig.10
141
Recommended tool length (mm)
Valve box
Valve box
Fig.9
Nitrogen cylinder
150
200
250
300
450
600