Design Technical Manual

2. PIPING DESIGN
2-1. IMPORTANT ITEMS WHEN USING REFRIGERANT R410A
R410A operates at higher pressure and has less solubility with mineral oil than
traditional R22 refrigerant. Therefore, 410A systems use a di󰀨erent lubricant and have di󰀨erent
piping requirements.
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REFRIGERANT PIPING MATERIAL AND WALL THICKNESS
Only seamless copper tube should be used for the refrigerant piping.
Thickness of tubes are shown in table below.
Endurance pressure of the pipe must be 609 psi (4.2 MPa).
Nominal Diameter (in.) 1/4" 3/8" 1/2" 5/8" 3/4" 7/8" 1-1/8" 1-3/8" 1-5/8"
Outside Diameter (mm) 6.35 9.52 12.70 15.88 19.05 22.22 28.58 34.92 41.27
Material JIS H3300 C1220T-O or equivalent *1 JIS H3300 C1220T-H or equivalent *2
Wall Thickness *3 (mm) 0.8 0.8 0.8 1.0 1.2 1.0 1.0 1.2 1.43
*1: Allowable tensile stress ≥ 33 (N/mm
2
)
*2: Allowable tensile stress ≥ 61 (N/mm
2
)
*3: Endurance pressure of the pipe must be 609 psi (4.2 MPa).
Select the pipe size in accordance with the regional standard.
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LUBRICANT
Refrigerant R410A (Mixed refrigerant)
Lubricant Synthetic oil
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TOOLS
R410A work requires a number of special tools. The items below (*) are specialized for R410A use.
Make sure that R22 tools are not used on R410A systems.
Tool name Process and application
Pipe cutter Pipe cutting
Refrigerant piping work
Flaring tool * Pipe aring work
Torque wrench * Flare nut connection
Expander Expansion at pipe connection
Pipe bender Pipe bending work
Nitrogen gas Pipe interior oxidation prevention
Pressure test
Welder Pipe brazing
Gauge manifold *
Vacuum evacuation and refrigerant
charging Operation check
Pressure Test/Additional Refrigerant
Charging
Charging hose *
Vacuum pump (with adaptor) * Vacuum drying
Electronic scale for refrigerant charging
Additional Refrigerant Charging
Gas leakage test4 Gas leakage test
*: Refer to a service manual for details.
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SYSTEM DESIGN SYSTEM DESIGN