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6. REFRIGERANT R410A
This air conditioner adopts the new refrigerant HFC
(R410A) which does not damage the ozone layer.
The working pressure of the new refrigerant R410A
is 1.6 times higher than conventional refrigerant
(R22). The refrigerating oil is also changed in
accordance with change of refrigerant, so be careful
that water, dust, and existing refrigerant or refriger-
ating oil are not entered in the refrigerant cycle of
the air conditioner using the new refrigerant during
installation work or servicing time.
The next section describes the precautions for air
conditioner using the new refrigerant.
Conforming to contents of the next section together
with the general cautions included in this manual,
perform the correct and safe work.
6-1. Safety During Installation/Servicing
As R410A’s pressure is about 1.6 times higher than
that of R22, improper installation/servicing may
cause a serious trouble. By using tools and materi-
als exclusive for R410A, it is necessary to carry out
installation/servicing safely while taking the following
precautions into consideration.
1. Never use refrigerant other than R410A in an air
conditioner which is designed to operate with
R410A.
If other refrigerant than R410A is mixed, pressure
in the refrigeration cycle becomes abnormally
high, and it may cause personal injury, etc. by a
rupture.
2. Confirm the used refrigerant name, and use tools
and materials exclusive for the refrigerant R410A.
The refrigerant name R410A is indicated on the
visible place of the outdoor unit of the air condi-
tioner using R410A as refrigerant.
To prevent mischarging, the diameter of the
service port differs from that of R22.
3. If a refrigeration gas leakage occurs during
installation/servicing, be sure to ventilate fully.
If the refrigerant gas comes into contact with fire,
a poisonous gas may occur.
4. When installing or removing an air conditioner,
do not allow air or moisture to remain in the
refrigeration cycle.
Otherwise, pressure in the refrigeration cycle
may become abnormally high so that a rupture
or personal injury may be caused.
5. After completion of installation work, check to
make sure that there is no refrigeration gas
leakage.
If the refrigerant gas leaks into the room, coming
into contact with fire in the fan-driven heater,
space heater, etc., a poisonous gas may occur.
6. When an air conditioning system charged with a
large volume of refrigerant is installed in a small
room, it is necessary to exercise care so that,
even when refrigerant leaks, its concentration
does not exceed the marginal level.
If the refrigerant gas leakage occurs and its
concentration exceeds the marginal level, an
oxygen starvation accident may result.
7. Be sure to carry out installation or removal
according to the installation manual.
Improper installation may cause refrigeration
trouble, water leakage, electric shock, fire, etc.
8. Unauthorized modifications to the air conditioner
may be dangerous. If a breakdown occurs
please call a qualified air conditioner technician
or electrician.
Improper repair’s may result in water leakage,
electric shock and fire, etc.
6-2. Refrigerant Piping Installation
6-2-1. Piping Materials and Joints Used
For the refrigerant piping installation, copper pipes
and joints are mainly used.
Copper pipes and joints suitable for the refrigerant
must be chosen and installed.
Furthermore, it is necessary to use clean copper
pipes and joints whose interior surfaces are less
affected by contaminants.
1. Copper Pipes
It is necessary to use seamless copper pipes
which are made of either copper or copper alloy
and it is desirable that the amount of residual oil
is less than 40 mg/10 m.
Do not use copper pipes having a collapsed,
deformed or discolored portion (especially on
the interior surface).
Otherwise, the expansion valve or capillary tube
may become blocked with contaminants.
As an air conditioner using R410A incurs pres-
sure higher than when using R22, it is necessary
to choose adequate materials.
Thicknesses of copper pipes used with R410A
are as shown in Table 6-2-1. Never use copper
pipes thinner than 0.8mm even when it is avail-
able on the market.
NOTE:
Refer to the “6-6. Instructions for Re-use Piping
of R22 or R407C”.