Mitsubishi Electric CITY MULTI PUHY-HP-TJMU-A Instruction Manual page 7

3 Branching cannot be made after header branching (corresponding parts are
marked with in the diagram below).
To the outdoor unit
To the outdoor unit
4 Do not install outdoor unit piping when it is raining.
5 Commercially available piping often contains dust and other materials.
Always blow it clean with a dry inert gas.
6 Use care to prevent dust, water or other contaminants from entering the
piping during installation.
7 Reduce the number of bending portions as much as possible, and make
bending radius as big as possible.
8 For indoor and outdoor branching, be sure to use the following twinning pipe
sets in the table 1 (sold separately).
9 Use an adapter if a specified refrigerant pipe has a different diameter from
that of a branching pipe.
<Table 1>
Downstream indoor unit capacity
Downstream indoor unit capacity
More than 73 and less than
Less than 72 in total
CMY-Y102SS-G2
Copper pipe size and radial thickness for R410A CITY MULTI.
Radial thickness
Size (mm) Size (inch)
(mm)
ø6.35 ø1/4" 0.8
ø9.52 ø3/8" 0.8
ø12.7 ø1/2" 0.8
ø15.88 ø5/8" 1.0
*ø19.05 ø3/4" 1.2
*ø19.05 ø3/4" 1.0
ø22.2 ø7/8" 1.0
ø25.4 ø1" 1.0
ø28.58 ø1-1/8" 1.0
ø31.75 ø1-1/4" 1.1
ø34.93 ø1-3/8" 1.2
ø41.28 ø1-5/8" 1.4
* Both pipe types can be used for pipe size ø19.05 (3/4 inch) for R410A air
conditioner.
CAP
Indoor twinning pipe set model
Line branch
Downstream indoor unit capacity
More than 145 and less than
144 in total 288 in total
CMY-Y102LS-G2 CMY-Y202S-G2
Radial thickness
Pipe type
(mil)
32 Type-O
32 Type-O
32 Type-O
40 Type-O
48 Type-O
40 Type-1/2H or H
40 Type-1/2H or H
40 Type-1/2H or H
40 Type-1/2H or H
44 Type-1/2H or H
48 Type-1/2H or H
56 Type-1/2H or H
0 Braze only with non-oxide brazing material for piping. Failure to do so
may damage the compressor. Be sure to perform the non-oxidation
brazing with a nitrogen purge.
Do not use any commercially available anti-oxidizing agent since it may
cause pipe corrosion and degrading of the refrigerant oil.
Please contact Mitsubishi Electric for more details.
(Refer to item 10.2. for details of the piping connection and valve operation)
a Always insulate the piping properly. Insufficient insulation will result in a
decline in heating/cooling performance, water drops from condensation
forming and other such problems. (Refer to item 10.4 for thermal insulation
of refrigerant piping.)
b When connecting the refrigerant piping, make sure the valve of the outdoor
unit is completely closed (the factory setting). 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.
c Never use refrigerant to perform an air purge. Always evacuate using a
vacuum pump.
d Be sure to charge the system using liquid refrigerant.
e Either a lack or an excess of refrigerant causes the unit to make an
emergency stop. Charge the system with an appropriate amount of
refrigerant. 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 item 9.2. for detailed information on refrigerant piping system.)
Header branch
4 branches 8 branches 10 branches
CMY-Y104C-G CMY-Y108C-G CMY-Y1010C-G
Warning:
When installing and moving the unit, do not charge the system with any
other refrigerant other than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to
malfunction and may result in severe damage.
Caution:
• Use a vacuum pump with a reverse flow check valve.
- If the vacuum pump does not have a reverse flow check valve, the vacuum
pump oil may flow back into the refrigerant cycle and cause deterioration of
the refrigerant oil.
• Do not use the tools shown below used with conventional refrigerant.
(Gauge manifold, charge hose, gas leak detector, check valve,
refrigerant charge base, vacuum gauge, refrigerant recovery
equipment)
- Mixing of conventional refrigerant and refrigerator oil may cause the
refrigerant oil to deteriorate.
- Mixing of water will cause the refrigerant oil to deteriorate.
- R410A refrigerant does not contain any chlorine. Therefore, gas leak
detectors for conventional refrigerants will not react to it.
• Manage the tools used for R410A more carefully than normal.
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerant oil will
deteriorate.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerant 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.
• Do not use special detergents for washing piping.
Outdoor Twinning Kit model
Total outdoor model
P144 ~ P192
CMY-Y100CBK2
7