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Countermeasures when exceeding the limit concentration
a. Please install a mechanical ventilation device.
b. If it is impossible to change air frequently, please install
a leak detection alarm device connected with the
mechanical ventilation device.
4.3 Selecting and Preparing the
Refrigerant Piping
4.3.1 Refrigerant piping requirements
NOTE
The R410A refrigerant pipeline system must be
kept strictly clean, dry and sealed.
Cleaning and drying: prevent foreign objects
(including mineral oil or water) from mixing
into the system.
Seal: R410A does not contain fluorine, does
not destroy the ozone layer, and does not
deplete the ozone layer that protect the earth
from harmful ultraviolet radiation. But if it is
released, R410A can also cause a slight
greenhouse effect. Therefore, you must pay
special attention when you check the sealing
quality of the installation.
The piping and other pressure vessels must
comply with the applicable laws and suitable
for use with the refrigerant. Use only
phosphoric acid deoxidized seamless copper
for the refrigerant piping.
Foreign objects in the pipes (including
lubricant used during pipe bending) must be
≤ 30 mg/10m.
Calculate all piping lengths.
4.3.2 Allowable length and height
difference for refrigerant piping
Refer to the following table and figure (for
reference only) to determine the appropriate size.
NOTE
The equivalent length of each elbow and
U-shape branch joint is 0.5m, the equivalent
length of each branch header is 1m.
As much as possible, install the indoor units
such that they are equidistant on both sides
of the U-shape branch joint.
When the outdoor unit is above the indoor
unit, and the level difference exceeds 20 m, it
is recommended that an oil return bend be
set up at every 10 m interval on the gas pipe
of the main piping. The recommended
specifications of the oil return bend are as
shown in figure 4.12.
Special-purpose branch joints from dealer for
all branch joints should be used. Failing to do
so may lead to severe system malfunction.
The first connect methond
Max. pipe length L ≤ 60m
Table 4.1
Max. actual length of pipe (L)
Height difference
between indoor unit
and outdoor unit (H)
The second connect methond
Outdoor unit
Piping between farthest indoor unit
and branch joint ≤ 15m
a
L1
A
Equivalent length of piping
between farthest indoor
The
unit and outdoor unit ≤ 65m
branch
joint
b
Fig. 4.11
Table 4.2
Total piping length
Piping between
Actual length
farthest indoor unit
and outdoor unit
Equivalent length
Piping between farthest
indoor unit and branch joint
Outdoor unit is
Largest level difference
above
between indoor unit and
Outdoor unit is
outdoor unit
below
Largest level difference
between indoor units
Indoor unit
Fig. 4.10
Allowed
value
60m
Outdoor
30m
(upper)
Outdoor
20m
(lower)
Indoor unit
Permitted
Piping
values
≤ 70m
L1+a+b
≤ 60m
L1+a or
L1+b
≤ 65m
≤ 15m
a,b
≤ 30m
≤20m
≤ 8m
V.1
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