5. Installation information
YKB/YLM 2nd
4 - 120
S.D. R2
MEE15K022
5-1-6. Unit installation
Your local distributor or a qualified technician must read the Installation Manual that is provided with each unit carefully
before performing installation work.
Consult your local distributor or a qualified technician when installing the unit. Improper installation by an unqualified
person may result in water leakage, electric shock, or fire.
Ensure there is enough space around each unit.
5-1-7. Optional accessories
Only use accessories recommended by Mitsubishi Electric. Consult your local distributor or a qualified technician when
installing them. Improper installation by an unqualified person may result in water leakage, electric leakage, system
breakdown, or fire.
Some optional accessories may not be compatible with the air conditioning unit to be used or may not suitable for the
installation conditions. Check the compatibility when considering any accessories.
Note that some optional accessories may affect the air conditioner's external form, appearance, weight, operating
sound, and other characteristics.
5-1-8. Operation/Maintenance
Read the Instruction Book that is provided with each unit carefully prior to use.
Maintenance or cleaning of each unit may be risky and require expertise. Read the Instruction Book to ensure safety.
Consult your local distributor or a qualified technician when special expertise is required such as when the indoor unit
needs to be cleaned.
5-2. Precautions for Indoor unit
5-2-1. Operating environment
The refrigerant (R410A) used for air conditioner is non-toxic and nonflammable. However, if the refrigerant leaks, the
oxygen level may drop to harmful levels. If the air conditioner is installed in a small room, measures must be taken to
prevent the refrigerant concentration from exceeding the safety limit even if the refrigerant should leak.
If the units operate in the cooling mode at the humidity above 80%, condensation may collect and drip from the indoor
units.
5-2-2. Unit characteristics
The return air temperature display on the remote controller may differ from the ones on the other thermometers.
The clock on the remote controller may be displayed with a time lag of approximately one minute every month.
The temperature using a built-in temperature sensor on the remote controller may differ from the actual room tempera-
ture due to the effect of the wall temperature.
Use a built-in thermostat on the remote controller or a separately-sold thermostat when indoor units installed on or in
the ceiling operate the automatic cooling/heating switchover.
The room temperature may rise drastically due to Thermo OFF in the places where the air conditioning load is large
such as computer rooms.
Be sure to use a regular filter. If an irregular filter is installed, the unit may not operate properly, and the operation noise
may increase.
The room temperature may rise over the preset temperature in the environment where the heating air conditioning load
is small.
5-2-3. Unit installation
For simultaneous cooling/heating operation type air conditioners (R2, WR2 series), the G-type BC controller cannot be
connected to the 16HP outdoor unit model or above, and the G- and GA-type BC controllers cannot be connected to the
28HP model or above. The GB- and HB-type BC controllers (sub) cannot be connected to the outdoor unit directly, and
be sure to use them with GA- and HA-type BC controllers (main).
The insulation for low pressure pipe between the BC controller and outdoor unit shall be at least 20 mm thick. If the unit
is installed on the top floor or in a high-temperature, high-humidity environment, thicker insulation may be necessary.
Do not have any branching points on the downstream of the refrigerant pipe header.
When a field-supplied external thermistor is installed or when a device for the demand control is used, abnormal stop of
the unit or damage of the electromagnetic contactor may occur. Consult your local distributor for details.
When indoor units operate a fresh air intake, install a filter in the duct (field-supplied) to remove the dust from the air.
The 4-way or 2-way Airflow Ceiling Cassette Type units that have an outside air inlet can be connected to the duct, but
need a booster fan to be installed at site. Refer to the chapter "Indoor Unit" for the available range for fresh air intake
volume.
Operating fresh air intake on the indoor unit may increase the sound pressure level.
