Cooling Circuit Connection To The Condensing Unit; Type Of Copper To Be Used For The Cooling Line; General Information For The Completion Of The Cooling Line; Connection Of The Pipes To The Machine - Mitsubishi Electric MULTIDENSITY 009 Installations, Bedienungs Und Wartungsanleitungen

MULTIDENSITY
2.3 COOLING CIRCUIT CONNECTION TO THE CONDENSING
UNIT
The cooling circuit connection must be completed as defined in the design phase.
Connections are normally inside the m-MRAC unit and can be accessed from the back
panel.
OBLIGATION
The oxide that forms inside the pipe during the brazing process is
dissolved by the HFC fluids and causes obstruction of the
refrigerant filter. During the brazing process it is advisable to
introduce nitrogen into the piping. If this is not possible, after
completing the brazing operation wash the piping using solvents.
OBLIGATION
The cooling circuits must be completed by qualified personnel.
All the works, the choice of the components and the materials used
must comply with the "Good Practices", according to the
regulations in force in the different countries, taking into account
the intended operating conditions and uses of the equipment.
Errors in the design and/or connection of the cooling circuits can
cause irreparable damage to the compressor (installed on the m-
MOCU condensing unit) or malfunctioning of the machine.
The indoor unit is delivered with nitrogen pressurised cooling
circuit. The refrigerant charge must be carried out on site by the
installer.
Do not open the taps during the completion of the cooling line with
the m-MOCU condensing unit.
2.3.1

TYPE OF COPPER TO BE USED FOR THE COOLING LINE

SOFT COPPER: It's soft and malleable, and can be shaped or bent to make bends,
siphons, etc. Use a pipe bending tool for the bending activities. Avoid
repeated bending or shaping, as the material will gradually harden at the
point of the bend and may break.
HARD COPPER: It's rather stiff, and not suitable for being bent. Only to be used for straight
sections. To make bends, siphons, etc. use forged fittings.
In any case, refer to local laws for better specification on the type of copper to use.
2.3.2

GENERAL INFORMATION FOR THE COMPLETION OF THE COOLING LINE

The cooling line must have a rational and practical path, in order to:

limit pressure drops

reduce the refrigerant content

facilitate the return of lubricant oil to the compressor (m-MOCU condensing unit)

facilitate the flow of liquid refrigerant to the expansion valve

prevent the return of liquid refrigerant with the compressor stopped

vertical sections must be reduced to the minimum.

always make large bends, with a minimum radius at least equal to the diameter of the
pipe.

always use a roller tube cutter to cut the pipes. Do not use a saw, as it causes internal
burrs and shavings.

fix the pipes both horizontally and vertically with copper or plastic collars every 2 m.

do not use galvanized iron collars, since corrosion may occur at the point of contact
with the copper pipe.

for insulated pipes, it is advisable to use collars with insulating shells.

keep a distance of at least 20 mm between the piping lines.

do not place electric cables nearby, as they may deteriorate.

make "expansion joints" on the line, to balance the natural elongation / shrinkage of
the pipes, as shown in the figure:
OBLIGATION
DO NOT OPEN THE MACHINE COOLING CIRCUIT TAPS
2.3.3

CONNECTION OF THE PIPES TO THE MACHINE

On the suction and liquid pipes, inside the machine, there are cooling circuit ball taps with
coupling copper pipe stub.
Complete the joint as following:
- Cut the end of the stub pipe using a roller tube cutter
- DO NOT USE A SAW AS IT WILL CAUSE BURRING
AND CHIPS
- Make a cup joint on the cooling piping and braze weld
the stub pipe
- Open the machine taps and empty using the service
ports (Ø 5/16").
- IF POSSIBLE, AVOID BRAZING ACTIVITIES
INSIDE THE MACHINE.
UM_MULTIDENSITY_00_Z_09_20_ML
LIQUID LINE TWINNING PIPE
outdoor
OD 3/8
Ø
unit 2
indoor
units
circuit
OD 5/8
Ø
First branch (branch joint)
TEE PIPES AND CONNECTION DIMENSIONING
For a correct pipe choice, the technician needs to consider the sum of the unit sizes of
all the connected internal units, following the below table:
Total down-stream indoor
UNIT SIZE
9 ~ 14
15 ~ 21
22 ~ 32
33 ~ 75
TEE CONNECTIONS DIMENSIONING
As above, the Tee connections are dimensioned considering the sum of indoor unit
sizes, following the table below:
Total indoor UNIT
SIZE
0 ~ 22
Ø 5/8" [Ø 15.88]
23 ~ 75
Ø 7/8" [Ø 22.2]
21
English
1x LIQUID LINE
1x GAS LINE
outdoor
unit 1
OD = Outer Diameter
ID = Inner Diameter
Example of connection between one outdoor unit
and more indoor units
Example of connection between two outdoor
units and more indoor units
Outdoor units twinning kit
First branch (branch joint)
Pipe
Liquid
Ø 1/2" [Ø 12.7] Ø 3/4" [Ø 19.05]
Ø 5/8" [Ø 15.88] Ø 7/8" [Ø 22.2]
Ø 3/4" [Ø 19.05] Ø 1" [Ø 25.4]
Ø 3/4" [Ø 19.05] Ø 1-1/8" [Ø 28.58]
TEE (F/F/F) size e code
Liquid
C7540341 Ø 7/8" [Ø 22.2]
C7540342 Ø 1" [Ø 25.4]
ORIGINAL INSTRUCTIONS
Gas
Gas
C7540342
C7540340