Panasonic CS-ME7DKEG Service Manual page 146

CS-ME7DKEG CS-ME10DD3EG / CS-ME10DTEG CS-E15DB4EW
13.3.3. Storing and Managing Piping Materials
1. Types of piping and their storage
The following is a general classification of the refrigerant pipe materials used for ACs.
Because the gas pressure of R410A is approximately 1.6 times as high as that of R22, copper pipes with the thickness shown
in Table 10, and with minimal impurities must be used. Care must also be taken during storage to ensure that pipes are not
crushed, deformed, or scratched, and that no dust, moisture or other substance enters the pipe interior. When storing sheathed
copper pipes or plain copper pipes, seal the openings by pinching or taping them securely.
2. Makings and management
a. Sheathed copper pipes and copper-element pipes
When using these pipes, check to make sure that they are the stipulated thickness. For flare nuts, be sure to used the same
nut that is used on the AC unit.
b. Copper pipes
Use only copper pipes with the thickness given in table 10, and with minimal impurities. Because the surface of the pipe is
exposed, you should take special care, and also take measures such as marking the pipes to make sure they are easily
distinguished from other piping materials, to prevent mistaken use.
3. Precautions during refrigerant piping work
Take the following precautions on-site when connecting pipes. (Keep in mind that the need to control the entry of moisture and
dust is even more important that in conventional piping).
a. Keep the open ends of all pipes sealed until connection with AC equipment is complete.
b. Take special care when doing piping work on rainy days. The entering of moisture will degrade the refrigerating machine oil,
and lead to malfunctions in the equipment.
c. Complete all pipe connections in as short a time as possible. If the pipe must be left standing for a long time after removing
the seal, it must be thoroughly purged with nitrogen, or dried with a vacuum pump.
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