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 refrig-
erant. Therefore, R410A systems use a different lubricant and have different piping requirements.
• Refrigerant piping material and wall thickness
Only seamless copper tubes should be used for refrigerant piping. Thickness of tubes are shown
in table below.
Endurance pressure of the pipes 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
Outside diameter mm 6.35 9.52 12.70 15.88 19.05 22.22 28.58
Material
JIS H3300 C1220T-O or equivalent*
1
JIS H3300 C1220T-H
or equivalent*
2
Wall thickness*
3
mm 0.8 1.0 1.2 1.0
– *1: Allowable tensile stress ≥ 33 N/mm
2
– *2: Allowable tensile stress
≥ 61 N/mm
2
– *3: Endurance pressure of the pipes must be 609 psi (4.2 MPa).
Select the pipe size in accordance with the regional standard.
• Lubricant
Refrigerant R410A (Mixed refrigerant)
Lubricant FVC68D
• Tools
R410A work requires a number of special tools. The items below (with * symbol) are specialized
for R410A. Make sure that R22 tools cannot be used on R410A systems.
Tool name Process and application
Pipe cutter Pipe cutting
Refrigerant piping work
Flaring tool* Pipe flaring work
Torque wrench* Flare nut connection
Expander Expansion at pipe connection
Pipe bender Pipe bending work
Nitrogen gas Pipe interior oxidation prevention
Air pressure test
Welder Pipe brazing
Gauge manifold* Vacuum evacuation and
refrigerant charging operation
check
Air pressure test through
Refrigerant additional charging
Charging hose*
Vacuum pump (with adapter)* Vacuum drying
Electronic scale for refrigerant
charging
Refrigerant additional charging
Gas leak tester* Gas leakage test
*: For details, refer to the service manual.
2-1. Important items when using refrigerant (R410A) - (06-14) - 2. Piping design
SYSTEM
DESIGN
SYSTEM
DESIGN
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