25
Example 3 of refrigerant piping selection:
ODU
N
1
(28)
N
3
(28)
N
2
(28)
A
B
C
a
b
c
L
1
L
2
L
3
d
N4
Figure 14-4
1
(80)
The example below illustrates the piping selection procedure for
a system consisting of 1 ODU (8 kW) and 4 IDUs (3 VRF IDUs
(2.8 kW × 3) and 1 hydraulic module (8.0 kW × 1)), as shown in
Figure 14-4.
The system's total equivalent piping length for all liquid and gas
pipes is not more than 90 m.
● Select the main pipe (L1) and first branch joint (A)
The ODU capacity is 8 kW, and the equivalent piping length of all
liquid and gas pipes is not greater than 90 m.
According to Table 14-4, the main gas liquid pipe size is Φ15.9
and Φ9.52 respectively.
The capacity of downstream IDUs is 8.4 kW (The capacity of the
hydraulic module does not need to be included).
Then refer to Table 14-6, the main gas/liquid pipe size is Φ15.9/
Φ9.52.
Referring to the max value principle, the gas and liquid pipe
sizes are Φ15.9/Φ9.52 and the first branch joint A is FQZHN-
01D.
● Select the indoor main pipe (L2 to L3) and branch joint (B to C)
The downstream IDUs of L2 are N1 to N2, with the capacity of
5.6 kW. Referring to Table 14-6, the gas and liquid pipe size of
L2 are Φ12.7 and Φ6.35respectively, and the branch joint B is
FQZHN-01D.
The downstream IDUs of L3 are N5 to N6, with the capacity of
2.8 kW (The capacity of the hydraulic module does not need
to be included). Referring to Table 14-6 and the max value
principle, the gas and liquid pipe sizes of L3 are Φ15.9 and
Φ9.52 respectively, and the branch joint C is FQZHN-01D.
● Select the IDU auxiliary pipe (a to d)
The capacity of IDU N1 to N3 is all less than 6.3 kW. According
to Table 14-7, the pipe size from a to c is respectively Φ12.7
and Φ6.35. According to Table 14-7, the pipe size d is
respectively Φ15.9 and Φ9.52.
14.2 Connecting Refrigerant Piping
14.2.1 Things to Note When Connecting
the Refrigerant Piping
● Take appropriate precautions to prevent refrigerant
leakage and ventilate the area immediately if the
refrigerant leaks, as high concentration of R32
refrigerant in an enclosed area can cause poisoning
or fire.
● Refrigerant must be recovered. Do not release it into
the environment. Use professional fluorine extraction
equipment to extract the refrigerant from the unit.
Caution
● Make sure the refrigerant piping is installed in
accordance with applicable laws.
● Make sure the piping and connections are not placed
under pressure.
● Before brazing, the refrigerant piping shall be
flushed with oxygen free nitrogen (OFN) to remove
dust, moisture and other particles. Never use ODU
refrigerant.
● Do not open the stop valves until confirming that all
the piping connections have been completed and
there are no gas leaks in the system.
Caution
14.2.2 Refrigerant Piping Connection
● Please be careful to avoid the components while
connecting to the connecting pipes.
● Low temperature solder alloys, such as lead/tin
alloys, are not acceptable for pipe connections or any
other refrigerant pressure containing purposes.
● Vacuum before welding, if necessary, to ensure that
there is no R32 residue in the piping.
● Oxygen free nitrogen (OFN) shall be purged through
the system both before and during the brazing
process.
Caution
14.2.2.1 Outdoor refrigerant piping
position
Various piping and wiring patterns can be selected, such as
exiting from the front, the back, the side, and bottom, etc.
(The following displays the locations of several piping and
wiring knock-out holes)
Connection of flaring (8/10 kW)
Figure 14-5
Side connection
Summary of Contents for KMF-80 DVR5
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