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12
ENGLISH
6 If the diameters of the branch piping of the designated refrigerant piping differs, use a pipe cutter to cut the connecting section and then use an
adapter for connecting different diameters to connect the piping.
7 Always observe the restrictions on the refrigerant piping (such as rated length, the difference between high/low pressures, and piping diameter).
Failure to do so can result in equipment failure or a decline in heating/cooling performance.
8 A second branch cannot be made after a header branch. (These are shown by ×.)
A
A
B
A To Outdoor Unit
B Capped Piping
9 Always use good-quality materials for brazing.
0 The City Multi Series Y will stop due an abnormality due to excessive or insufficient coolant. At such a time, always properly charge the unit. When
servicing, always check the notes concerning pipe length and amount of additional refrigerant at both locations, the refrigerant volume calculation
table on the back of the service panel and the additional refrigerant section on the labels for the combined number of indoor units. (Refer to Pages
13
to
14
.)
A Use liquid refrigerant to fill the system.
B Never use refrigerant to perform an air purge. Always evacuate using a vacuum pump.
C Always insulate the piping properly. Insufficient insulation will result in a decline in heating/cooling performance, water drops from condensation
and other such problems. (Refer to Pages
21
to
22
.)
D When connecting the refrigerant piping, make sure the ball valve of the outdoor unit is completely closed (the factory setting) and do not operate it
until the refrigerant piping for the outdoor and indoor units has been connected, a refrigerant leakage test has been performed and the evacuation
process has been completed.
E Always use a non-oxidizing brazing material for brazing the parts. If a non-oxidizing brazing material is not used, it could cause clogging or damage
to the compressor unit. (Details of the piping connections and valve operation can be found on Pages
15
to
16
.)
F Never perform outdoor unit piping connection work when it is raining.
Warning:
When installing and moving the air conditioner to another site, do not charge the it with a refrigerant different from the refrigerant (R407C)
specified on the unit.
- If a different refrigerant or air is mixed with the original refrigerant, the refrigerant cycle may malfunction and the unit may be damaged.
Caution:
• Use refrigerant piping made of C1220T-OL phosphorus deoxidized copper. In addition, be sure that the inner and outer surfaces of the
pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shaving particles, oils, moisture, or any other contaminant.
- Contaminants on the inside of the refrigerant piping may cause the refrigerant residual oil to deteriorate.
• Use liquid refrigerant for sealing.
- Sealing with gas refrigerant will change the composition of the refrigerant in the cylinder and reduce the unit’s performance.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil in the existing piping will cause the new refrigerant to deteriorate.
• Store the piping to be used during installation indoors and keep both ends of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and the compressor may fail.
• Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
Total of units down-
stream more than 331
Total of units down-
stream less than 160
Total of units down-
stream 161 to 330
10.1. Areas of caution
1 Use the following materials for refrigeration piping.
• Material: Seamless phosphorous deoxidized copper pipe, C1220T-OL or C1220T-O (Note: C1220T-OL is preferred.)
• Size: Refer to Pages
13
to
14
.
2 Commercially available piping often contains dust and other materials. Always blow it clean with a dry inert gas.
3 Use care to prevent dust, water or other contaminants from entering the piping during installation.
4 Reduce the number of bending portions as much as possible, and make bending radius as big as possible.
5 Always use the branch piping set shown below, which are sold separately.
Branch pipe set name
Line branching Header branching
4 branching 7 branching 10 branching
CMY-Y102S-F CMY-Y102L-F CMY-Y202-F CMY-Y104-E CMY-Y107-E CMY-Y1010-E