Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

Page: 5 / 436

iv
[4] Piping Work
[5] Wiring Work
Piping Work
Piping work shall be kept to a minimum.
The pipes shall be protected from physical
damage.
Before heating the brazed sections, remove
the gas and oil that are trapped in the pipes.

Failure to do so may generate fire, resulting in serious
injury.
Do not purge the air using refrigerant. Use a
vacuum pump to evacuate the system.

Residual gas in the refrigerant lines will cause bursting
of the pipes or an explosion.
Do not use oxygen, flammable gas, or a re-
frigerant containing chlorine for air-tight-
ness testing.

Doing so may result in an explosion. Chlorine will dete-
riorate the refrigerant oil.
When installing or relocating the unit, do
not allow air or any substance other than
the specified refrigerant to enter the refrig-
erant lines.

Any substance other than the specified refrigerant may
cause abnormally high pressure in the refrigerant
lines, resulting in bursting of the pipes or an explosion.
After the installation has been completed,
check for refrigerant leaks.

If the refrigerant leaks, oxygen starvation may result. If
the leaked refrigerant comes in contact with a heat
source, toxic gas will be generated.
Have a fire extinguisher nearby before braz-
ing work.

If the refrigerant leaks while brazing work is being per-
formed, fire may result.
Provide no-smoking signs at the brazing
workplace.

If the refrigerant leaks when an ignition source is pres-
ent, fire may result.
Wiring Work
Include some slack in the power cables.

Failure to do so may break or overheat the cables, re-
sulting in smoke or fire.
Connections must be made securely and
without tension on the terminals.

Improperly connected cables may break, overheat, or
cause smoke or fire.
Tighten all terminal screws to the specified
torque.

Loose screws and contact failure may result in smoke
or fire.
Electrical work must be performed by quali-
fied personnel in accordance with local reg-
ulations and the instructions provided in
this manual. Only use the specified cables
and dedicated circuits.

Inadequate power source capacity or improper electri-
cal work will result in electric shock, malfunction, or
fire.
Install an inverter circuit breaker on the
power supply of each unit.

Failure to do so may result in electric shock or fire.
Only use properly rated breakers (an earth
leakage breaker, local switch <a
fuse that meets local electrical codes>, or
overcurrent breaker).

Failure to do so may result in electric shock, malfunc-
tion, smoke, or fire.
Only use standard power cables of suffi-
cient capacity.

Failure to do so may result in current leakage, over-
heating, smoke, or fire.
Proper grounding must be provided by
qualified personnel.

Improper grounding may result in electric shock, fire,
explosion, or malfunction due to electrical noise. Do
not connect the ground wire to gas or water pipes,
lightning rods, or telephone ground wires.
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