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, the lubricant and a part of pipe material are dierent.
Some special tools are necessary.
REFRIGERANT PIPING MATERIAL AND WALL THICKNESS
It is necessary to use seamless copper tubes for refrigerant use.
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"
Outside Diameter (mm) 6.35 9.52 12.70 15.88 19.05
Material JIS H3300 C1220T-O or equivalent *1
Wall Thickness *2 (mm) 0.8 0.8 0.8 1.0 1.2
*1: Allowable tensile stress ≥ 33 (N/mm
2
)
*2: Endurance pressure of the pipe must be 609 psi (4.2 MPa).
Select the pipe size in accordance with regional standard.
LUBRICANT
Refrigerant R410A (Mixed refrigerant)
Lubricant Synthetic oil
TOOLS
R410A work requires a number of special tools. Since the tools (with * symbol) for R22 work
cannot be used for R410A, prepare them beforehand.
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
Air tightness test
Welder Pipe brazing
Gauge manifold *
Vacuum evacuation and refrigerant
charging Operation check
Air tightness test ~
Refrigerant additional charging
Charging hose *
Vacuum pump (with adaptor) * Vacuum drying
Electronic scale for refrigerant charging
Refrigerant additional charging
Gas leak tester * Gas leakage test
*: Refer to a service manual for details.
- (06 - 12) -
SYSTEM
DESIGN
SYSTEM
DESIGN
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