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7. 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 refrigerat-
ing 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.
7-1. 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, pres-
sure in the refrigeration cycle becomes abnor-
mally 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.
7-2. Refrigerant Piping Installation
7-2-1. 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 discol-
ored 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
pressure higher than when using R22, it is
necessary to choose adequate materials.
Thicknesses of copper pipes used with R410A
are as shown in Table 7-2-1. Never use copper
pipes thinner than 0.8 mm even when it is
available on the market.