Panasonic CU-E18CKR Service Manual page 63

10.3.3. 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 surethey 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.