R410A All DC Inverter V5 X Series 50Hz      MCAC-VTSM-2015-10 
98 Installation 
4.  Refrigerant pipe installation 
4.1  Basic requirements 
4.1.1  Operation procedure 
 
4.1.2  Three principles for refrigerant piping 
Rainwater/Engineered water / 
Condensation may enter the piping 
system 
The  process  of  tubing  must  follow  standard  procedures  →  Blow 
cleanly → Vacuum 
Oxidation  produced  by  welding/Outside 
dust /Sundries 
Charge nitrogen gas to prevent oxidation when welding/Attention the 
cleanness during the piping process → Blow clean 
Imprecision  welding/Unqualified  airproof 
to bell-mouth/Leakage of the fringe 
Use  suitable  welding  rod  to  weld/Comply  with  welding  operation 
criteria/Comply with bell-mouth connecting operation criteria/Comply 
with the interface operation criteria →Air seal test 
Caution: Removing oil from copper pipe of a system that uses R410A 
For the system that uses R410A, oil-free copper pipes should be selected (they can also be customized). If ordinary (oily) copper 
pipes are used, it must be cleaned with gauze that is dipped into tetrachloroethylene solution. 
Purpose of cleaning copper pipe: Remove the lubrication (industrial oil used during the processing of the copper pipe) attached to 
the inner wall of the copper pipe. The ingredients of such lubricants are different from those of the lubricants used by the R410A 
refrigerant, and will leave deposits in the system, which may cause complex system errors. 
Special Note: Never use CCl4 for pipe cleansing and flushing, or the system will be seriously damaged. 
4.1.3  Support for refrigerant pipe 
1. Fixing horizontal pipe 
When the air conditioner is running, the refrigerant pipe will deform (for example, shrunk/expanded or droop). 
To avoid pipe damage, use hangers or supports (see the table below for the criteria). 
Interval between support points (m) 
In general, gas pipe and liquid pipe should be suspended in parallel, and the interval between support points 
should be selected according to the diameter of the gas pipe. The temperature of the flowing refrigerant will 
change according to operation and working conditions, which will result in expansion and shrinkage of the 
refrigerant piping, therefore piping with thermal insulation should not be clamped tightly, in order to avoid any 
rupturing of the copper piping as a result of unnecessary stress. 
2. Fixing vertical piping 
Fix the pipe along the wall according to the pipeline route. Round log should be used at the pipe clip to replace 
thermal insulation material, “U”-shape pipe should be fixed outside the round log, and the round log should be 
provided with anticorrosion treatment. 
Interval between support points (m) 
   
Determine the route and size of the pipeline according to the construction drawing 
Make and install brackets, hangers and supports 
Make and arrange pipe accessories → Recharge nitrogen gas for protection 
Welding → Pipe flushing → Air seal test → Thermal insulation → Vacuum