8Piping Works And Flaring TechniqueDo not use contaminated or damaged copper tubing. Ifany piping, evaporator or condenser had been exposed orhad been opened for 15 seconds or more, the system mustbe vacuumed. Generally do not remove plastic, rubberplugs and brass nuts from the valves, fittings, tubing andcoils until it is ready to connect suction or liquid line intovalves or fittings.If any brazing work is required, ensure that nitrogen gasis passed through coil and joints while the brazing workis being done. This will eliminate soot formation on theinside wall of copper tubings.Cut the pipe stages by stages, advancing the blade of pipecutter slowly. Extra force and a deep cut will cause moredistortion of pipe and therefore extra burr. See Figure A.Remove burrs from cut edges of the pipes with remover. SeeFigure B. Hold the pipe on top position and burr removerat lower position to prevent metal chips from entering thepipe. This will avoid unevenness on the flare faces whichwill cause gas leak.Insert the flare nuts, mounted on the connection parts ofboth the indoor unit and outdoor unit, into the copperpipes.The exact length of pipe protruding from the top surfaceof the swaging block is determined by the flaring tool. SeeFigure C.Fix the pipe firmly on the swaging block. Match the centersof both the swaging block and the flaring punch, thentighten the flaring punch fully.Piping Connection To The UnitsAlign the center of the piping and tighten the flare nutsufficiently with fingers. See Figure D.Finally, tighten the flare nut with torque wrench until thewrench clicks.When tightening the flare nut with the torque wrench,ensure that the tightening direction follows the arrowindicated on the wrench.The refrigerant pipe connection are insulated by closedcell polyurethane.•••••••••••1/4tCutting Copper TubeCopper TubeSwaging BlockRemove BurrCopper TubeFigure ADAPipe Size mm/(in) Torque Nm/(ft-Ib)6.35 (1/4") 18 (13.3)12.70 (1/2") 55 (40.6)15.88 (5/8") 65 (48.0)Flared TubeFlare JointFlare NutIndoor PipingTorque WrenchSpanarØ Tube, D A (mm)Inch mm Imperial(Wing-nut Type)Rigid(Clutch Type)1/4" 6.35 1.3 0.71/2" 12.70 1.9 1.35/8" 15.88 2.2 1.7Figure BFigure CFigure D