Refrigerant R410A; Refrigerant Piping Installation - Toshiba RAS-M10PKVP-E Service Manual

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 refrigerating 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.
3-1. 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 materials
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 conditioner
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.

3. Refrigerant R410A

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 may result in water leakage, electric
shock and fire, etc.

3-2. Refrigerant Piping Installation

3-2-1. 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 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 3-2-1.
Never use copper pipes thinner than 0.8 mm even
when it is available on the market.
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