Refrigerant Piping Installation - Toshiba RAS-07PKVP-E Service Manual

High Wall, Heat Pump Type

2-2. Refrigerant Piping Installation

2-2-1. Piping Materials and Joints Used
For the refrigerant piping installation, copper pipes and joints are mainly used.
Copper pipes and joints suitable for the refrigerant must be chosen and installed.
Furthermore, it is necessary to use clean copper pipes and joints whose interior surfaces are less affected by
contaminants.
Copper Pipes
It is necessary to use seamless copper pipes which are made of either copper or copper alloy and it is desirable
that the amount of residual oil is less than 40 mg/10 m.
Do not use copper pipes having a collapsed, deformed or discoloured portion (especially on the interior surface).
Otherwise, the expansion valve or capillary tube may become blocked with contaminants.
As an air conditioner using R410A incurs pressure higher than when using R22, it is necessary to choose adequate
materials.
Thicknesses of copper pipes used with R410A are as shown in Table 2-2-1. Never use copper pipes thinner than
0.8 mm even when it is available on the market.
Table 2-2-1 Thicknesses of annealed copper pipes
Nominal diameter
1/4
3/8
1/2
5/8
Joints
For copper pipes, flare joints or socket joints are used. Prior to use, be sure to remove all contaminants.
• Flare Joints
Flare joints used to connect the copper pipes cannot be used for pipings whose outer diameter exceeds 20 mm.
In such a case, socket joints can be used.
Sizes of flare pipe ends, flare joint ends and flare nuts are as shown in Tables 2-2-3 to 2-2-6 below.
• Socket Joints
Socket joints are such that they are brazed for connections, and used mainly for thick pipings whose diameter is
larger than 20 mm.
Thicknesses of socket joints are as shown in Table 2-2-2.
Table 2-2-2 Minimum thicknesses of socket joints
Nominal diameter
1/4
3/8
1/2
5/8
2-2-2. Processing of Piping Materials
When performing the refrigerant piping installation, care should be taken to ensure that water or dust does not enter
the pipe interior, that no other oil than lubricating oils used in the installed air-water heat pump is used, and that
refrigerant does not leak.
When using lubricating oils in the piping processing, use such lubricating oils whose water content has been
removed. When stored, be sure to seal the container with an airtight cap or any other cover.
Outer diameter (mm)
6.35
9.52
12.70
15.88
Reference outer diameter of
copper pipe jointed (mm)
6.35
9.52
12.70
15.88
14
Thickness (mm)
R410A
0.80
0.80
0.80
1.00
Minimum joint thickness
Service Manual
R22
0.80
0.80
0.80
1.00
(mm)
0.50
0.60
0.70
0.80