Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

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[1-2 Handling and Characteristics of Piping Materials, Refrigerant, and Refrigerant Oil ]
BS_01_G
chapter 1 -
3
1
Che
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Se
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1-2 Handling and Characteristics of Piping Materials,
Refrigerant, and Refrigerant Oil
1-2-1 Piping Materials
1. Copper pipe materials

The distinction between O-materials (Annealed) and 1/2H-materials (Drawn) is made based on the strength of the pipes them-
selves.

O-materials (Annealed) can easily be bent with hands.

1/2H-materials (Drawn) are considerably stronger than O-material (Annealed) at the same thickness.
2. Types of copper pipes
3. Piping materials/Radial thickness
Use refrigerant pipes made of phosphorus deoxidized copper.
The operation pressure of the units that use R32 is higher than that of the units that use R22.
Use pipes that have at least the radial thickness specified in the chart below.
(Pipes with a radial thickness of 0.7 mm or less may not be used.)

Annealed pipes have been used for older model units when a diameter of the pipe is up to
φ
19.05 (3/4"). For a system that
uses R410A or R32, use pipes that are made with 1/2H-material (Drawn). (Annealed pipes may be used for pipes with a di-
ameter of
φ
19.05 (3/4") and a radial thickness of 1.2 t).

The figures in the radial thickness column are based on the Japanese standards and provided only as a reference. Use pipes
that meet the local standards.
4. Thickness and refrigerant type indicated on the piping materials
Ask the pipe manufacturer for the symbols indicated on the piping material for new refrigerant.
O-material (Annealed) Soft copper pipes (annealed copper pipes). They can easily be bent with hands.
1/2H-material (Drawn) Hard copper pipes (straight pipes). They are stronger than the O-material (Annealed)
at the same radial thickness.
Maximum working pressure Refrigerant type
3.45 MPa [500psi] R22, R407C etc.
4.30 MPa [624psi] R410A, R32 etc.
Pipe size (mm[in]) Radial thickness (mm) Type
ø6.35 [1/4"] 0.8t
O-material (Annealed)
ø9.52 [3/8"] 0.8t
ø12.7 [1/2"] 0.8t
ø15.88 [5/8"] 1.0t
ø19.05 [3/4"] 1.0t
1/2H-material,
H-material (Drawn)
ø22.2 [7/8"] 1.0t
ø25.4 [1"] 1.0t
ø28.58 [1-1/8"] 1.0t
ø31.75 [1-1/4"] 1.1t
ø34.93 [1-3/8"] 1.2t
ø41.28 [1-5/8"] 1.4t
Do not use the existing piping!
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