Refrigerant Piping Installation; Caution - Mitsubishi Electric City Multi PUHY-HP200YHM-A Installationshandbuch

9. Refrigerant piping installation

The pipe is connected via a terminal-branch type connection in which refrigerant
piping from the outdoor unit is branched at the terminal and is connected to each
of the indoor units.
The method of pipe connection is as follows: flare connection for the indoor units,
gas pipes and liquid pipes for outdoor units, brazed connection. Note that the branched
sections are brazed.
Warning:
Do not use refrigerant other than the type indicated in the manuals provided
with the unit and on the nameplate.
- Doing so may cause the unit or pipes to burst, or result in explosion or fire during
use, during repair, or at the time of disposal of the unit.
- It may also be in violation of applicable laws.
- MITSUBISHI ELECTRIC CORPORATION cannot be held responsible for mal-
functions or accidents resulting from the use of the wrong type of refrigerant.
Always use extreme care to prevent the refrigerant gas from leaking while
using fire or flame. If the refrigerant gas comes in to contact with a flame
from any source, such as a gas stove, it breaks down and generates a poi-
sonous gas which can cause gas poisoning. Never weld in an unventilated
room. Always conduct an inspection for gas leakage after installation of the
refrigerant piping has been completed.

Caution:

• Do not vent R410A into the atmosphere.
• R410A is a Fluorinated Greenhouse gas, covered by the Kyoto Protocol
with a Global Warming Potential (GWP) = 1975.
9.1. Caution
This unit uses refrigerant R410A. Follow the local regulations on materials and
pipe thickness when selecting pipes. (Refer to the table on the right.)
1 Use the following materials for refrigeration piping.
• Material: Use copper alloy seamless pipes made of phosphorus deoxi-
dized copper. Ensure the inner and outer surfaces of the pipes are clean
and free from hazardous sulfur, oxide, dusts, shaving particles, oils, and
moisture (contamination).
• Size: Refer to item 9.2. for detailed information on refrigerant piping sys-
tem.
Downstream indoor unit capacity
Downstream indoor unit capacity
More than 201 and less than
Less than 200 in total
CMY-Y102SS-G2
8 Branching cannot be made after header branching (corresponding parts are
marked with in the diagram below).
To the outdoor unit
To the outdoor unit
9 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 serv-
icing, 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 infor-
mation on refrigerant piping system).
14
Indoor twinning pipe set model
Line branch
Downstream indoor unit capacity
More than 401 and less than
400 in total 650 in total
CMY-Y102LS-G2 CMY-Y202S-G2
CAP
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 bend-
ing radii as big as possible.
5 For indoor and outdoor branching, be sure to use the following twinning pipe
sets (sold separately).
Copper pipe size and radial thickness for R410A CITY MULTI.
Size (mm) Size (inch) Radial thickness (mm)
ø6.35 ø1/4"
ø9.52 ø3/8"
ø12.7 ø1/2"
ø15.88 ø5/8"
ø19.05 ø3/4"
ø19.05 ø3/4"
ø22.2 ø7/8"
ø25.4 ø1"
ø28.58 ø1-1/8"
ø31.75 ø1-1/4"
ø34.93 ø1-3/8"
ø41.28 ø1-5/8"
* For pipe sized ø19.05 (3/4") for R410A air conditioner, choice of pipe type is up
to you.
6 Use a fitting if a specified refrigerant pipe has a different diameter from that of
a branching pipe.
7 Always observe the restrictions on the refrigerant piping (such as rated length,
height difference, and piping diameter) to prevent equipment failure or a de-
cline in heating/cooling performance.
Header branch
4 branches 8 branches
CMY-Y104-G CMY-Y108-G CMY-Y1010-G
0 Be sure to charge the system using liquid refrigerant.
A Never use refrigerant to perform an air purge. Always evacuate using a
vacuum pump.
B Always insulate the piping properly. Insufficient insulation will result in a de-
cline in heating/cooling performance, water drops from condensation and other
such problems (Refer to item 10.4 for thermal insulation of refrigerant piping).
C When connecting the refrigerant piping, make sure the 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 re-
frigerant leakage test has been performed and the evacuation process has
been completed.
D Braze only with non-oxide brazing material for piping. Failure to do so
may damage the compressor. Be sure to perform the non-oxidation braz-
ing 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)
E Never perform outdoor unit piping connection work when it is raining.
Pipe type
0.8 Type-O
0.8 Type-O
0.8 Type-O
1.0 Type-O
1.2 Type-O
1.0 Type-1/2H or H
1.0 Type-1/2H or H
1.0 Type-1/2H or H
1.0 Type-1/2H or H
1.1 Type-1/2H or H
1.2 Type-1/2H or H
1.4 Type-1/2H or H
Outdoor Twinning Kit model
Total outdoor model
10 branches
P400 ~ P500
CMY-Y100VBK2