Installation Of Unit; Installation; Connecting Direction For Refrigerant Piping; Refrigerant Piping Installation - Mitsubishi Electric CITY MULTI PUHY-P-YEM-A Serie Installationshandbuch

7. Installation of unit

7.1. Installation

[Fig. 7.1.1] (P.2)
A M10 anchor bolt procured at the site.
• Fix unit tightly with bolts so that unit will not fall down due to earthquake or gust
of wind.
• Use concrete or angle bracket for foundation of unit.
• Vibration may be transmitted to the installation section and noise and vibration
may be generated from the floor and walls, depending on the installation con-
ditions. Therefore, provide ample vibrationproofing (cushion pads, cushion
frame, etc.).
• Be sure that the corners are firmly seated. If the corners are not firmly seated,
the installation feet may be bent.
Warning:
• Be sure to install unit in a place strong enough to withstand its weight.
Any lack of strength may cause unit to fall down, resulting in a personal
injury.
• Have installation work in order to protect against a strong wind and earth-
quake.
Any installation deficiency may cause unit to fall down, resulting in a
personal injury.

8. 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.
The method of connection consists of flare connections at the indoor units, flange
connections for the piping of the outdoor unit and flare connections for the liquid
piping. Note that the branched sections are brazed.
Warning:
Always use extreme care to prevent the refrigerant gas (R407C) from leaking
while using fire or flame. If the refrigerant gas comes in contact with the
flame from any source, such as a gas stove, it breaks down and generates a
poisonous 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.

8.1. Caution

1 Use the following materials for refrigeration piping.
• Material: Use refrigerant piping made of 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. (For R407C models)
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 radius as big as possible.
5 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.
6 The City Multi Y Series will stop due to 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 addi-
tional refrigerant at both locations, the refrigerant volume calculation table on
the back of the service panel and the additional refrigerant section on the la-
bels for the combined number of indoor units.
7 Use liquid refrigerant to fill the system.
8 Never use refrigerant to perform an air purge. Always evacuate using a vacuum
pump.
9 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.
0 When connecting the refrigerant piping, make sure the ball valve of the out-
door 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.
A 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.
When building the foundation, give full attention to the floor strength, drain water
disposal <during operation, drain water flows out of the unit>, and piping and wir-
ing routes.
B Corner is not seated.
Down piping and down wiring precautions
When down piping and down wiring are performed, be sure that foundation and
base work does not block the base through holes. When down piping is performed,
make the foundation at least 150 mm high so that the piping can pass under the
bottom of the unit.
[Fig. 7.1.2] (P.3)
7.2. Connecting direction for refrigerant pip-
[Fig. 7.2.1] (P.3)
B Never perform outdoor unit piping connection work when it is raining.
When installing and moving the unit, do not charge it with refrigerant other
than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal-
function and result in severe damage.
• Use a vacuum pump with a reverse flow check valve. (For R407C models)
- If the vacuum pump does not have a reverse flow check valve, the vacuum
• Do not use the tools shown below used with conventional refrigerant.
(For R407C models)
(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 refrig-
- Mixing of water will cause the refrigerator oil to deteriorate.
- R407C refrigerant does not contain any chlorine. Therefore, gas leak detec-
• Manage the tools more carefully than normal. (For R407C models)
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerator oil will dete-
• Never use existing refrigerant piping. (For R407C models)
- The large amount of chlorine in conventional refrigerant and refrigerator oil
• 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
• Do not use a charging cylinder. (For R407C models)
- Using a charging cylinder may cause the refrigerant to deteriorate.
• Do not use special detergents for washing piping.

8.2. Refrigerant piping system

Connection Example (PUHY-P400/500YEM-A)
[Fig.8.2.1] (P.3)
Note:
• The model total for downstream units shown in the table below is the
model total when viewed from Point A in the drawing above.
A Bottom piping through hole
C (bolt hole for old models)
ing
A Knock-out hole
C Front piping
D Connect piping (to constant capacity unit) (In the case of Super-Y)
Warning:
Caution:
pump oil may flow back into the refrigerant cycle and cause deterioration of
the refrigerator oil and other trouble.
erator oil to deteriorate.
tors for conventional refrigerants will not react to it.
riorate.
in the existing piping will cause the new refrigerant to deteriorate.
the compressor may fail.
Å Liquid line
Ç Total capacity of indoor units
‰ Downstream unit model total
Ì 4 branching header
¬ 10 branching header
A Outdoor unit
B First branch
The first branch on the outdoor unit must be the CMY-Y202-F.
C Indoor unit
B (bolt hole)
D Bottom wiring through hole
B Bottom piping
ı Gas line
Î Model number
Ï Branch kit model
Ó 7 branching header
D To downstream units
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