2. ABOUT THE UNIT
2.1. Precautions for using R410A refrigerant
The basic installation work procedures are the same
as conventional refrigerant (R22) models.
However, pay careful attention to the following points:
(1) Since the working pressure is 1.6 times higher
than that of conventional refrigerant (R22)
models, some of the piping and installation and
service tools are special. (See the table below.)
Especially, when replacing a conventional
refrigerant (R22) model with a new refrigerant
R410A model, always replace the conventional
piping and ﬂ are nuts with the R410A piping and
ﬂ are nuts.
(2) Models that use refrigerant R410A have a
different charging port thread diameter to
prevent erroneous charging with conventional
refrigerant (R22) and for safety. Therefore, check
beforehand. [The charging port thread diameter
for R410A is 1/2 inch.]
(3) Be more careful that foreign matter (oil, water,
etc.) does not enter the piping than with
refrigerant (R22) models. Also, when storing the
piping, securely seal the opening by pinching,
(4) When charging the refrigerant, take into account
the slight change in the composition of the gas
and liquid phases. And always charge from the
liquid phase where refrigerant composition is
2.2. Special tools for R410A
Pressure is high and cannot be
measured with a conventional (R22)
gauge. To prevent erroneous mixing
of other refrigerants, the diameter of
each port has been changed.
It is recommended the gauge with
seals-0.1 to 5.3 MPa (30 in.Hg to
768 psi) for high pressure.
-0.1 to 3.8 MPa (30 in.Hg to 551 psi)
for low pressure.
To increase pressure resistance, the
hose material and base size were
A conventional vacuum pump can be
used by installing a vacuum pump
Special gas leakage detector for
Gas leakage detector
HFC refrigerant R410A.
Contents of change
It is necessary to use seamless copper pipes and it is
desirable that the amount of residual oil is less than
0.004 oz/100ft. Do not use copper pipes having a collapsed,
deformed or discolored portion (especially on the interior sur-
face). Otherwise, the expansion value or capillary tube may
become blocked with contaminants.
As an air conditioner using R410A incurs pressure higher than
when using R22, it is necessary to choose adequate materials.
CONNECTION PIPE REQUIREMENT
(1) Do not use the existing (for R22) piping and ﬂ are nuts.
• If the existing materials are used, the pressure inside
the refrigerant cycle will rise and cause failure, injury,
etc. (Use the special R410A materials.)
(2) When installing and relocating the air conditioner,
do not mix gases other than the speciﬁ ed refriger-
ant (R410A) to enter the refrigerant cycle.
• If air or other gas enters the refrigerant cycle, the
pressure inside the cycle will rise to an abnormally
high value and cause failure, injury, etc.
2.3. For authorized service personnel only.
• For the air conditioner to operate satisfactorily, install it as
outlined in this installation manual.
• Connect the indoor unit and outdoor unit or branch box
with the air conditioner piping and cables available from
your local distributor. This installation manual describes
the correct connections using the installation set available
from your local distributor.
• Installation work must be performed in accordance with
national wiring standards by authorized personnel only.
• Do not turn on the power until all installation work is
This installation manual describes how to install the in-
door unit only.
To install the outdoor unit, refer to the installation manual
included with the outdoor unit or branch box.
• Be careful not to scratch the air conditioner when han-
• After installation, explain correct operation to the cus-
tomer, using the operating manual.