Design Technical Manual

Table Of Contents
3. PIPING CONNECTION
3-1. PIPING PRECAUTIONS
CAUTION
Stay within all piping limitations to prevent system damage or malfunction.
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Piping material
Use the designated size ( Diameter & thickness ) of refrigerant pipes.
Those pipes purchased locally may contain dust inside. Use dry nitrogen to blow out any duct.
Do not use standard pipe Tees for branches , these can cause uneven refrigerant flow to the indoor units. Fujitsu
branch kits should be used instead.
T-tube
Prohibited OK
Separation tube
Reducer
Never reuse refrigerant pipe. Only new pipe should be used.
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Pipe Preparation and Installation
Make sure that no dust or water enters the pipe during preparation or installation.
When installing the pipe make as few bends as possible and make radiuses as large as possible.
Cut the branch kit at the right size or use the reducer to match the pipe to the branch kit.
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Brazing
While Brazing the pipes, be sure to blow dry nitrogen gas through them.
If nitrogen gas is not blown through the pipes while they are being brazed, an oxidized layer may form on the
inside of the pipes. If this occurs, the cooling efficiency may decrease and the air conditioner unit (compressor,
valves, etc.) be damaged.
0.02MPa
Pressure hose
Rubber stopper
Bellows valve
Nitrogen gas
When brazing the pipes, do not use flux. If the flux is chlorine-based, the pipes will corrode and when the flux
contains fluorine, the refrigerant oil will deteriorate, etc. Using the flux has an adverse affect on the refrigerant
piping system.
For brazing materials, use phosphor copper solder that does not require flux.
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Piping treatment
The pipes vibrate, expand, and contract during operation, so if loads are concentrated in one area, it could cause
cracks in the pipes. Provide the pipe supports every 6ft.6-3/4in to 9ft.10-1/8in. (2 to 3m)
Make sure to insulate both refrigerant lines separately with the appropriately sized insulation as described earlier.
Make sure to overlap the ends to prevent any gaps.
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