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01_EN_3P281953-1B.fm Page 13 Tu esday, January 25, 2011 3:35 PM
Precautions when re-using pre-existing refrigerant piping
• Abide by the following when re-using pre-existing refrigerant piping. Any problems with the piping may lead
to malfunctioning.
• In the following cases, do not re-use piping, but rather lay new piping.
· If indoor or outdoor units have been disconnected from the piping for a long time (as water and foreign
matter might have entered the piping).
· If copper piping is corroded.
• Flares should be redone and not re-used, in order to prevent refrigerant leaks.
• Do not reuse the flare nuts. Instead, use the flare nuts included with the product.
• Check for refrigerant leaks on welded areas if the pre-existing piping has been welded anywhere.
• Replace any deteriorated insulation with new insulation.
6-2 INSTALLATION TOOLS
Be sure to use the dedicated tools to ensure sufficient pressure resistance and prevent the entry of
any impurities.
To ensure sufficient pressure resistance and prevent the entry of any impurities (mineral
Manifold gauge
oils such as Suniso oil and liquids), use the R410A dedicated item (the screw specifica-
Charging hose
tions for R410A and R407C differ).
Be extremely careful not to flow the pump oil backward to inside the piping when the
Vacuum pump
pump is stopped.
Use a pump whose gauge pressure can vacuum up to –0.1 MPa (–755 mmHg).
6-3 SELECTING PIPING MATERIALS
Use the piping whose inside and outside are clean and with no harmful substances for use such as sulphur,
oxide, dust, dust from cutting, grease, or liquid (contamination) is attached.
For the refrigerant piping, use the following material.
Material: Deoxidised phosphorous seamless copper pipe
Thickness and size: Decide based on section 6-5 REFRIGERANT PIPE SIZE AND ALLOWABLE PIPE
LENGTH.
For the handling of the stop valves, refer to "Precautions when the handling piping stop valves" in section
6-6 REFRIGERANT PIPING WORK.
Be sure to perform piping work using measurements within the maximum allowable length and height
difference described in 6-5 REFRIGERANT PIPE SIZE AND ALLOWABLE PIPE LENGTH.
6-4 PIPING PROTECTION
Protect the piping and prevent liquid, dirt and dust from entering into the piping.
Pay special attention when running the copper pipe through the through-hole or when leading the edge of the
pipe outside the room.
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