Panasonic CS-MVG103KE Service Manual

Panasonic CS-MVG103KE Service Manual Manual pdf 46 page image

10.3. REFRIGERANT PIPING WORK10.3.1. Piping MaterialsIt is recommended that you use copper and copper alloy jointless pipes with a maximum oil adherence of 40 mg/10 m. Do not usepipes that are crushed, deformed, or discolored (especially the inside surface). If these inferior pipes are used, impurities may clogthe expansion valves or capillaries.Because the pressure of ACs using R410A is higher than those using R22, it is essential that you select materials that areappropriate for these standards.The thickness of the copper tubing used for R410A is shown in Table 10. Please be aware that tubing with a thickness of only 0.7mm is also available on the market, but this should never be used.Table 10 Copper tube thickness (mm)Soft pipe Thickness (mm)Nominal diameter Outside diameter (mm) R410A (Reference)R221/4 6.35 0.80 0.803/8 9.52 0.80 0.801/2 12.7 0.80 0.8010.3.2. Processing and Connecting Piping MaterialsWhen working with refrigerant piping, the following points must be carefully observed: no moisture or dust must be allowed to enterthe piping, and there must be no refrigerant leaks.1. Procedure and precautions for flaring worka. Cut the pipeUse a pipe cutter, and cut slowly so the pipe will not be deformed.b. Remove burrs and clean shavings from the cut surfaceIf the shape of the pipe end is poor after removing burrs, or ifshavings adhere to the flared area, it may lead to refrigerant leaks.To prevent this, turn the cut surface downward and remove burrs,then clean the surface, carefully.c. Insert the flare nut (be sure to use the same nut that is used on theAC unit)d. FlaringCheck the clamp bar and the cleanliness of the copper pipe.Be sure to use the clamp bar to do the flaring with accuracy.Use either an R410A flaring tool, or a conventional flaring tool.Flaring tools come in different sizes, so be sure to check the sizebefore using. When using a conventional flaring tool, use thecopper pipe gauge for clearance adjustment, etc., to ensure thecorrect A dimension (see Fig. 10)Fig. 10 Flaring dimensionsFig. 11 Relation between the flare nut structure and flaring tool endTable 11 R410A flaring dimensionsNominaldiameterOutsidediameter(mm)Wall thickness(mm)A(mm)R410A flaringtool, clutch typeConventional flaring toolClutch type Wing-nut type1/4 6.35 0.8 0 - 0.5 1.0 - 1.5 1.5 - 2.03/8 9.52 0.8 0 - 0.5 1.0 - 1.5 1.5 - 2.01/2 12.70 0.8 0 - 0.5 1.0 - 1.5 2.0 - 2.546CS-MVG103KE / CU-MVG153KE