Panasonic U-36LE1U6 Installation Instructions Manual

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Panasonic U-36LE1U6 Installation Instructions Manual Manual pdf 27 page image

27Caution Before Connecting Tubes Tightly(1) Apply a sealing cap or water-proof tape to prevent dust orwater from entering the tubes before they are used.(2) Be sure to apply refrigerant lubricant to the matchingsurfaces of the flare and union before connecting themtogether. This is effective for reducing gas leaks. (Fig. 5-4)(3) For proper connection, align the union tube and flare tubestraight with each other, then screw in the flare nut lightlyat first to obtain a smooth match. (Fig. 5-5)● Adjust the shape of the liquid tube using a tube bender atthe installation site and connect it to the liquid tubing sidevalve using a flare.Cautions During Brazing● Replace air inside the tube with nitrogen gas toprevent copper oxide film from forming during thebrazing process. (Oxygen, carbon dioxide and Freonare not acceptable.)● Do not allow the tubing to get too hot during brazing.The nitrogen gas inside the tubing may overheat,causing refrigerant system valves to become dam-aged.Therefore allow the tubing to cool when brazing.● Use a reducing valve for the nitrogen cylinder.● Do not use agents intended to prevent the formationof oxide film.These agents adversely affect therefrigerant and refrigerant oil, and may cause damageor malfunctions.5-2. Connecting Tubing Between Indoor and OutdoorUnits(1) Tightly connect the indoor-side refrigerant tubing extendedfrom the wall with the outdoor-side tubing.(2) To fasten the flare nuts, apply specified torque as at right:● When removing the flare nuts from the tubing connections,or when tightening them after connecting the tubing, besure to use 2 adjustable wrenches or spanners as shown.(Fig. 5-6)If the flare nuts are over-tightened, the flare may be dam-aged, which could result refrigerant leakage and cause ininjury 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 atright.Apply refrigerantlubricantFig. 5-4Flare nutUnionFig. 5-5Fig. 5-6Indoor unitOutdoor unitSpannerTorque wrenchTube diameterø1/4"(ø6.35 mm)ø3/8"(ø9.52 mm)ø1/2"(ø12.7 mm)ø5/8"(ø15.88 mm)ø3/4"(ø19.05 mm)Tightening torque,approximate120 – 160 lbs · in.(140 – 180 kgf · cm)300 – 360 lbs · in.(340 – 420 kgf · cm)430 – 480 lbs · in.(490 – 550 kgf · cm)590 – 710 lbs · in.(680 – 820 kgf · cm)870 – 1040 lbs · in.(1000 – 1200 kgf · cm)1/32"(0.8 mm)1/32"(0.8 mm)1/32"(0.8 mm)5/128"(1.0 mm)over 5/128"(1.0 mm)Tube thicknessBecause the pressure is approximately 1.6 timeshigher than conventional refrigerant pressure, theuse of ordinary flare nuts (type 1) or thin-walledtubes may result in tube rupture, injury, orasphyxiation caused by refrigerant leakage.● In order to prevent damage to the flare caused byover-tightening of the flare nuts, use the tableabove as a guide when tightening.● When tightening the flare nut on the liquid tube,use an adjustable wrench with a nominal handlelength of 7-7/8".