5 Preparation
Installer and user reference guide
11
5TMV1B
VRV IV-S system air conditioner
4P404224-1 – 2015.03
room which is sufficiently large. This assures that the maximum
concentration level of refrigerant gas is not exceeded, in the unlikely
event of major leak in the system and this in accordance to the local
applicable regulations and standards.
About the maximum concentration level
The maximum charge of refrigerant and the calculation of the
maximum concentration of refrigerant is directly related to the
humanly occupied space in to which it could leak.
The unit of measurement of the concentration is kg/m
3
(the weight in
kg of the refrigerant gas in 1 m
3
volume of the occupied space).
Compliance to the local applicable regulations and standards for the
maximum allowable concentration level is required.
According to the appropriate European Standard, the maximum
allowed concentration level of refrigerant to a humanly space for
R410A is limited to 0.44 kg/m
3
.
b
a
a
Direction of the refrigerant flow
b
Room where refrigerant leak has occurred (outflow of all
the refrigerant from the system)
Pay special attention to places, such as basements etc., where
refrigerant can stay, since refrigerant is heavier than air.
To check the maximum concentration level
Check the maximum concentration level in accordance with steps 1
to 4 below and take whatever action is necessary to comply.
1
Calculate the amount of refrigerant (kg) charged to each system
separately.
Formula
A+B=C
A
Amount of refrigerant in a single unit system
(amount of refrigerant with which the system is
charged before leaving the factory)
B
Additional charging amount (amount of
refrigerant added locally in accordance with the
length or diameter of the refrigerant piping)
C
Total amount of refrigerant (kg) in the system
NOTICE
Where a single refrigerant facility is divided into 2 entirely
independent refrigerant systems, use the amount of
refrigerant with which each separate system is charged.
2
Calculate the volume of the room (m
3
) where the indoor unit is
installed. In a case such as the following, calculate the volume
of (A), (B) as a single room or as the smallest room.
A
Where there are no smaller room divisions:
B
Where there is a room division, but there is an opening
between the rooms sufficiently large to permit a free flow of air
back and forth.
a
b
a
Opening between the rooms
b
Partition (Where there is an opening without a door or where
there are openings above and below the door which are each
equivalent in size to 0.15% or more of the floor area.)
3
Calculate the refrigerant density using the results of the
calculations in steps 1 and 2 above. If the result of the above
calculation exceeds the maximum concentration level, a
ventilation opening to the adjacent room shall be made.
Formula
A/B≤C
A
Total volume of refrigerant in the refrigerant
system
B
Size (m
3
) of smallest room in which there is an
indoor unit installed
C
Maximum concentration level (kg/m
3
)
4
Calculate the refrigerant density taking the volume of the room
where the indoor unit is installed and the adjacent room. Install
ventilation openings in the door of adjacent rooms until the
refrigerant density is smaller than the maximum concentration
level.
5.3
Preparing refrigerant piping
5.3.1
Refrigerant piping requirements
INFORMATION
Also read the precautions and requirements in the
"General safety precautions" chapter.
NOTICE
The refrigerant R410A requires strict cautions for keeping
the system clean, dry and tight.
▪ Clean and dry: foreign materials (including mineral oils
or moisture) should be prevented from getting mixed
into the system.
▪ Tight: R410A does not contain any chlorine, does not
destroy the ozone layer, and does not reduce earth's
protection against harmful ultraviolet radiation. R410A
can contribute slightly to the greenhouse effect if it is
released. Therefore we should take special attention to
check the tightness of the installation.
NOTICE
The piping and other pressure-containing parts shall be
suitable for refrigerant. Use phosphoric acid deoxidised
seamless copper for refrigerant.
▪ Foreign materials inside pipes (including oils for fabrication) must
be ≤30 mg/10 m.
5.3.2
Refrigerant piping material
▪
Piping material:
Phosphoric acid deoxidised seamless copper.
▪
Piping temper grade and thickness:
