GMV5 Home DC Inverter Multi VRF Units
152
9.5 Installation and Insulation of Refrigerant Pipe
9.5.1 Pipe installation for cooling system
9.5.1.1 Processing to refrigerant pipes
9.5.1.1.1 Cut-off and burring
Warning! Use a special-purpose pipe cutter to cut copper pipes instead of using a
hacksaw.
1）Use a special-purpose pipe cutter to cut copper pipes;
2）Cut the pipes gently to ensure that the copper pipe does not deform;
3）After cutting the pipes, use a slicker to grater bur the pipes with the pipe opening inclining
downward so that the copper scales do not fall into the pipe;
4）If the copper pipe is not used immediately after cut-off, cover it with a sealing cap or
adhesive tape;
5）Allowable deviation: Skewness of the cross section cannot exceed 1% of the copper pipe
caliber.
9.5.1.1.2 Pipe cleaning
1）Cleaning with a piece of silk cloth-applicable to straight pipes
（1）Wrap a thin steel wire with a piece of clean silk cloth. Crumple the cloth into a lump with
diameter larger than the pipe caliber;
（2）Apply several drops of chlorylene to the cloth. Push the cloth in from one end of the pipe
and pull out from the other end;
（3）Every time the cloth is pulled out, remove the dust and sundries with chlorylene;
（4）Wash repeatedly until the pipe is clean.
2）Cleaning with nitrogen-applicable to coils
Blow off all dust and sundries in the pipe with nitrogen.
Warning! After cleaning, cover the both ends of the pipe with a sealing cap or
adhesive tape.
9.4.1.1.3 Pipe bending
Notices
During bending, there must be no corrugation or deformation inside the pipe.
The welding point of the pipe should not be at the bending part. The distance between the
nozzle welding joint and the bending part should not be less than 100 mm.
1）Processing requirements:
The radius of the bending pipe must exceed 3.5D. The ratio of the short diameter after
bending to the original diameter must exceed 2/3.
2）Processing methods:
（1）Manual bending: applies to thin copper pipes (Φ6.35 mm toΦ12.7 mm)
（2）Mechanical bending: applicable range (Φ6.35mm toΦ54.1mm)
9.4.1.1.4 Pipe expanding
Pipe expanding is used to provide a welding point for pipe connection. Requirements on pipe
expanding are as follows:
1）Before pipe expanding, apply appropriate amount of lubricant on the surface of the pipe.
(The lubricant must meet the refrigerant system’s requirements);
2）Pipe expanding length must be in accordance with the insertion depth of the caliber;
3）To avoid leakage due to straight lines at the expanding point, turn round the copper pipe
and then make corrections;
4）Apply appropriate force during pipe expanding to avoid crack.
9.4.1.1.5 Flaring
Another mode of pipe connection is flare opening connection, which requires pipe flaring
before connection.
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