Panasonic S-12MT2U6 Installation Instructions Manual

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Contents

17Cautions During Brazing● Replace air inside the tube with nitrogen gas to prevent copper oxide film from forming during the brazing process.(Oxygen, carbon dioxide and Freon are not acceptable.)● Do not allow the tubing to get too hot during brazing. The nitrogen gas inside the tubing may overheat, causingrefrigerant system valves to become damaged. Therefore allow the tubing to cool when brazing.● Use a reducing valve for the nitrogen cylinder.● Do not use agents intended to prevent the formation of oxide film. These agents adversely affect the refrigerant andrefrigerant oil, and may cause damage or malfunctions.5-2. Connecting Tubing Between Indoor and Outdoor Units(1) Tightly connect the indoor-side refrigerant tubing extended fromthe wall with the outdoor-side tubing.Indoor Unit Tubing Connection ( 1, 2 ... n-1)Indoor unit type 12, 18 24Gas tubing inch ø1/2 ø5/8mm ø12.7 ø15.88Liquid tubing inch ø1/4 ø3/8mm ø6.35 ø9.52(2) To fasten the flare nuts, apply specified torque as at right:Outdoor unitTorque wrenchSpannerIndoor unitFig. 5-6● When removing the flare nuts from the tubing connections, orwhen tightening them after connecting the tubing, be sure touse a torque wrench and a spanner. (Fig. 5-6)If the flare nuts are over-tightened, the flare may bedamaged, which could result in refrigerant leakage andcause injury or asphyxiation to room occupants.● For the flare nuts at tubing connections, be sure to use theflare nuts that were supplied with the unit, or else flare nutsfor R410A (type 2). The refrigerant tubing that is used mustbe of the correct wall thickness as shown in the table at right.Because the pressure is approximately 1.6 times higher thanconventional refrigerant pressure, the use of ordinary flarenuts (type 1) or thin-walled tubes may result in tube rupture,injury, or asphyxiation caused by refrigerant leakage.Tube diameter Tightening torqueapproximate Tube thicknessø1/4"(ø6.35 mm)lbf·inch 120 – 160 lbf·inch 1/32”N·m 14 – 18 N·m 0.8 mm{kgf·cm} {140 – 180 kgf·cm}ø3/8”(ø9.52 mm)lbf·inch 300 – 360 lbf·inch 1/32”N·m 34 – 42 N·m 0.8 mm{kgf·cm} {340 – 420 kgf·cm}ø1/2”(ø12.7 mm)lbf·inch 430 – 540 lbf·inch 1/32”N·m 49 – 61 N·m 0.8 mm{kgf·cm} {490 – 610 kgf·cm}ø5/8”(ø15.88mm)lbf·inch 590 – 710 lbf·inch 5/128”N·m 68 – 82 N·m 1.0 mm{kgf·cm} {680 – 820 kgf·cm}● In order to prevent damage to the flare caused by over-tightening of the flare nuts, use the table above as a guide whentightening.● When tightening the flare nut on the liquid tube, use an adjustable wrench with a nominal handle length of 7-7/8 in. (200 mm).