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English
7-1 Selecting piping material
CAUTION
Piping and other pressure containing parts shall comply with the
applicable legislation and shall be suitable for refrigerant. Use phos-
phoric acid deoxidized seamless copper for refrigerant.
CAUTION
• All field piping must be installed by a licensed refrigeration techni-
cian and must comply with relevant local and national regulations.
• After piping work is complete, do not under any circumstances
open the stop valve until
6. FIELD WIRING
on page 6 and
9. POST-WORK CHECKS
on page 13 are complete.
• Do not use flux when brazing the refrigerant piping. Use the phos-
phor copper brazing filler metal(B-Cu93P-710/795:ISO 3677)
which does not require flux. Flux has extremely negative effect on
refrigerant piping systems. For instance, if the chlorine based flux
is used, it will cause pipe corrosion or, in particular, if the flux con-
tains fluorine, it will damage the refrigerant oil.
• Use only pipes which are clean inside and outside and which do not
accumulate harmful sulfur, oxidants, dirt, cutting oils, moisture, or
other contamination. (Foreign materials inside pipes including oils
for fabrication must be 0.14 gr/10 ft. (30 mg/10 m) or less.)
• Use the following items for the refrigerant piping.
Material :
Jointless phosphor-deoxidized copper pipe.
Size :
See
7-6 Example of connection
.
Thickness :
Select a thickness for the refrigerant piping which com-
plies with national and local laws.
• Install the refrigerant branch kit while observing the following condi-
tion and referring to the installation manual offered as an accessory
of the kit.
(Refer to figure 20)
1.
Install the REFNET joint so it splits horizontally or vertically.
2.
Horizontal surface
3.
A-arrow view
4.
±30° or less
5.
Level
6.
Vertical is also OK
7.
Install the REFNET header so that it splits horizontally.
8.
B-arrow view
7-2 Protection against contamination when install-
ing pipes
• Wrap the piping to prevent moisture, dirt, dust, etc. from entering the
piping.
• Exercise caution when passing copper piping through the through-
holes and when passing them out to the outside.
• In case existing refrigerant pipes between outdoor and indoor are
being re-used, the line set must be flushed with R410A to avoid
residual oil from previous system contaminating the new system.
Remember to consult and follow all limitations for using existing pipe.
7-3 Pipe connection
• See “Stop valve operation procedure” in “
7-8 Air tight test and vac-
uum drying
” regarding handling of the stop valve.
• Only use the flare nuts included with the unit. Using different flare
nuts may cause the refrigerant to leak.
•
Be sure to perform a nitrogen blow when brazing.
(Brazing without performing nitrogen replacement or releasing nitro-
gen into the piping will create large quantities of oxidized film on the
inside of the pipes, adversely affecting valves and compressors in the
refrigerating system and preventing normal operation.)
(Refer to figure 21)
1.
Refrigerant pipe
2.
Location to be brazed
3.
Regulator
4.
Nitrogen
5.
Manual valve
6.
Taping
7-4 Connecting the refrigerant piping
• Connection to larger pipe sizes.
In certain configurations this system is designed to be connected to
larger diameter pipe sizes than the standard factory service valves.
If the installation requires use of larger pipe diameters, a field setting
change is required for the system to operate smoothly.
• A filter dryer should not be attached to piping.
• The local inter-unit piping is connectable in four directions.
(Refer to figure 22)
1.
Front panel
2.
Pipe outlet panel
3.
Backward
4.
Sideways
5.
Downward
6.
Pipe outlet panel screw
7.
Forward
8.
Screw for front panel
•
When connecting the pipings downward, remove the knockout
by making four holes in the middle on the each side of the
knockout with a drill.
(Refer to figure 23)
1.
Drill
2.
Center area around knockout hole
3.
Knockout hole
4.
Slit
• After knocking out the knock-out, it is recommended to apply repair
paint to the edge and the surrounding end surfaces to prevent rusting.
(Refer to figure 24)
1.
Bottom frame
2.
Interunit piping
3.
piping (accessory)
Limitations when using existing pipes.
When installing residential VRV you should use the specified pipe diam-
eter sizes and insulate both gas and liquid pipes.
An exception to this would be in a system replacement application where
existing piping can be used if the limitations listed below are followed.
1.
Limitations when using existing liquid pipes.
• Observe the piping size of 7-6.
• Using existing liquid pipes is allowed for the main pipe only. Ther-
mal insulation is required to branch pipes.
• Insulation is required to accessible liquid pipe exposed outdoors
and indoors.
• Liquid pipes which located under outdoor ambient condition should
to be insulated as much as possible.
• Condensation at non-insulation liquid pipe may cause a problem,
field pipe setting (Mode2-4) have to set “1” or “3”.
• If there is a place where insulation can not be installed, add the
amount of refrigerant according to “
7-7 Additional refrigerant
charge amount
”.
• Insulation on liquid pipe is required if there is possibility to operate
at reversed ambient temperatures between outdoor and indoor
(cooling: outdoor<indoor, heating: outdoor>indoor)
2.
Limitations when using existing gas pipes.
• Observe the piping size of 7-6.
• Using existing liquid pipes is allowed for the main pipe only.
Place
Installation Protection
method
More than a month
Pinch the pipe
Less than a month
Pinch or tape the pipe
Regardless of the period
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