Welding Of Refrigerant Pipe; Purging Of Refrigerant Pipe - Trane MWD507 Installation & Operation Manual

Welding of refrigerant pipe

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Purging of refrigerant pipe

During erecting and constructing the fi tting pipe, it is hard to avoid dust, water vapor entering the
pipe. Therefore, after completion of fi tting pipe construction, it is necessary to purge the pipe with
nitrogen.
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AMS-SVX04A-EN
Make downward or fl at lateral welding, and avoid overhead welding as possible;
For liquid or gas pipes, be sure to care the assembling direction and angle, and avoid refrigerant
short circuit or oil accumulation;
While welding, the allowed method to replacing nitrogen:
Nitrogen protection soldering must be used. During the welding, it is necessary to fi ll
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0.2 ~ 0.5 kgf/cm nitrogen in the fi tting pipe to prevent system blockage due to the oxide
generated in welding;
After fi nishing the welding, cool naturally or by purging nitrogen, but cold water spraying is
not allowed to avoid crack generation of the crater because of shock chilling.
Try to reduce the number of bends. When bending the pipe, the bending radius should be as
large as possible;
Standard space for supports of the pipe is as follows:
Welding zone
Manual valve
Nitrogen
Plug
Pressure regulato
Pressure hose
Nitrogen cylinder
Pressure regulator valve
Gas pipe
Liquid pipe
The gas used for purging must be nitrogen. The nitrogen cylinder should be equipped with a
pressure regulator valve.
Connect the pressure regulator valve to the inlet of the outdoor unit at the side of liquid pipe with
a gas pipe.
Block well all interfaces of the copper tube at the liquid side with blind plugs except those for the
indoor unit A.
Switch on the nitrogen cylinder, and adjust the valve to 5 Kgf/cm2.
Check whether the nitrogen passes through the liquid pipe to indoor unit A. (The interface at the
side of the indoor unit should be covered with adhesive tape to prevent dirt entering.)
Installation of refrigerant pipe
Pipe size 20 mm below
Max. interval (m) 1.0
Outdoor unit
A
B
Indoor unit
Interface not connected temporarily.
Cover the interface of the indoor unit with adhesive tape
20 ~ 45 mm 45 mm above
1.5 2.0
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