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2-2. Installing refrigerant pipe
2-2-1. Steel pipe and joint
For refrigerant piping, steel pipe and joints are mainly used. Select those comply with JIS (Japanese Industrial
Standards) for a service work. Also, use such clean piping materials that less impurities attach to the inside of pipe
and joints.
Copper pipe
Use copper pipe of the “copper and copper alloy seamless pipe” type with attach oil quantity of 40 mg / 10 m or less.
Do not use pipe that is cracked, distorted, or discolored (especially inside).The expansion valve or capillary may
get clogged with impurities.
Considering that Air to Water Heat Pump using R410A is higher in pressure than those using the conventional R22,
be sure to select the material that comply with the standard.
Table 2-1 shows the thickness of copper pipe used for R410A.
Never use commercially available thin-walled copper pipe of 0.8 mm thick or less.
Table 2-1 Wall thickness of copper pipe
Joints
For the joint of copper pipe, flared joint and socket joint are used. Remove impurities from a joint before using it.
• Flared joint
A flared joint cannot be used for the copper pipe whose outer diameter is 20 mm or larger. A socket joint can be
used instead in that case.
Table 2-2-3 and 2-2-4 show the dimensions of flare pipe, the end of flared joint, and flare nuts.
• Socket joint
A socket joint is used to connect the thick-walled pipe of mainly 20 mm or larger in diameter.
Table 2-2 shows the wall thickness of socket joints.
Table 2-2 The minimum wall thickness of socket joints
Wall thickness (mm)
Nominal diameter Outer diameter R410A
3/8 9.52 0.80
5/8 15.88 1.00
Nominal diameter
Reference of outer diameter of
copper pipe connected (mm)
Minimum joint wall thickness
(mm)
3/8 9.52 0.80
5/8 15.9 1.00
+00A09-002_01EN_SVM_ALL_Air_to_Water.book Page 7 Monday, October 5, 2009 2:09 PM