Refrigerant Piping Installation; Areas Of Caution - Mitsubishi Electric CITY MULTI PUMY-71 Manuel D'installation

Remove the service panel (three screws) and the piping cover (one
screw).
s Be careful not to break the bent portion when connecting the pipes.
Be sure to use two spanners to tighten the flare nuts.
Extraction direction
for service panel
Service panel

7. Refrigerant piping installation

Connecting the piping is a terminal-branch type in which refrigerant piping from the outdoor unit is branched at the terminal and connected to each of
the indoor units.
For the piping of outdoor unit, flare connection must be used. Note that the branched sections are brazed.

7.1. Areas of caution

1 Use the following materials for refrigeration piping.
• Material: Seamless phosphorous deoxidized copper pipe.
• Size: Refer to Pages 8 to 11.
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.
(Keep the number of bends for each indoor unit and outdoor unit to 15 or less.)
5 Always use the branch piping sets shown below, which are sold separately.
Line branching
CMY-Y62-C-E
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 It is not possible to re-branch after header branching and multi-distribution piping on outdoor unit has been done.
9 Always use good-quality, materials for brazing.
0 Carry out refrigerant charge correctly if refrigerant needs to be added. Both excess refrigerant or insufficient refrigerant can cause trouble. Make
sure to record the amount of charged refrigerant, together with the piping length, on the label provided on the front of the electric parts box so that
they can be referred to during customer service etc.
A Never use refrigerant to perform an air purge. Always evacuate using a vacuum pump. (Refer to Page 13)
B 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 Page 14)
C When connecting the refrigerant piping, make sure the stop 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, and a refrigerant leakage test has been performed and the
evacuation process has been completed.
(Details of the piping connections and valve operation can be found on Page 12)
Warning:
When installing or moving the unit to another location, never mix anything other than the designated refrigerant (R-22) in the refrigeration
cycle. If air or any other substance is mixed in, the pressure within the refrigeration cycle will become abnormally high and will cause
damage.
Caution:
Always use extreme care to prevent the freon gas (R-22) from leaking while using fire or flame. If freon gas comes in contact with the flame
from any source, such as gas stove, it breaks down and a poisonous gas is created which can cause gas poisoning. Never braze or weld in
an unventilated and/or closed area. Always conduct an inspection for gas leakage after the installation of the refrigeration piping has been
completed.
Stop valve
Bending radius
R 100 - 150 mm
Piping cover
Branch Pipe set name
Header branching
4 branching 8 branching
CMY-Y64-C CMY-Y68
When racking the pipes, keep the racking below the top of the pip-
ing cover to allow easy service panel removal.
Multi distribution piping on outdoor unit
5 branching
CMY-S65
Piping cover
Racking
7