Gree GRS-Cm28/NaA-M - Page 23

Chapter Ⅱ Installation（5. Installation and Heat Insulation for Pipelines of Water System）
21
Type
Material
Design Pressure (MPa)
PD≤0.6
0.6＜PD≤0.8
0.8＜PD≤1.0
Cold water pipe
PP-R
S5
S4
S4
Hot water pipe
PP-R
S3.2
S2.5
S2
5.1.2 Installation for pipelines of water system
When the PP-R pipe is connected by hot welding, the welding machines and tools should be
specially provided or acknowledged by pipe material manufacturers. The machines and tools for
welding should be safe and reliable and easy to be handled, and should have product certificate
of qualification and operating instruction manual.
Hot welding connection steps:
1）Energize the welding machine and tools, the machine can be used for welding only when it
reaches the working temperature（260±10℃）and the indicator is on.
2）Before connecting the pipes, the end of pipe is suggested to cut 40~50mm off, when
cutting the pipes, the end face should be vertical to the axial line of pipe. It is suggested to use
pipe clipper or pipe cutter or hacksaw to cut the pipes, after cutting the pipes, the rough selvedge
of cross section should be removed.
3）Connection end face of pipes and parts should be clean, dry and no oil.
4）Use calipers and pen to measure and mark the socket depth of pipe end, the socket depth
should not be less than the requirements in the following sheet;
5）Heating time, processing time and cooling time should be conducted according to the
manufacturer of hot welding machine. If there is no requirement, please refer to the following
sheet:
Technical Requirement of Hot Welding Connection
Nominal outer
diameter
（mm）
Minimum socket
depth
（mm）
Heating time
（s）
Processing time
（s）
Cooling time
（min）
20
11.0
5
4
3
25
12.5
7
4
3
32
14.6
8
4
4
40
17.0
12
6
4
50
20.0
18
6
5
63
23.9
24
6
6
75
27.5
30
10
8
90
32.0
40
10
8
110
38.0
50
15
10
Notes: the applicable temperature of the parameter in this sheet is 20℃. If it is lower than this temperature, the
heating time will be accordingly prolonged; if the ambient temperature is lower than 5℃, the heating time is
suggested to be prolonged for 50%.
6）When welding the bent pipe or tee joint, pay attention to the direction of the joint, indicate