Sharp AF-05CML Service Manual - Page 10

AF-05CML HOW TO REPAIR REFRIGERATION Before sealed system work can be preformed a refrigerant recovery EPA and LOCALLY approved certification is required, additionally, EPA and LOCALLY approved refrigerant recovery equipment is required. SEALED SYSTEM REPAIR Sealed system repairs should be properly diagnosed before entering into a repair of the system. It is important to follow proper procedures when doing a system repair for safety reasons and that the repair will result in a restoration of the system to proper factory standards. SAFETY REMINDERS 1) Do not heat any system component with an open flame for any reason. 2) Do not solder until you are sure that all refrigerant has been removed from the system. 3) Do not heat the charging cylinder with an open flame. Use warm water only and do not exceed 125˚F (not too hot to keep your hand in.) 4) Do not over fill any charging cylinders, as they could explode when over filled. 5) Use proper wrenches. 6) Use safety goggles when working with refrigerants. 7) Keep a fire extinguisher within easy reach. 8) Watch flame direction when soldering so as not to burn clothing, wiring or other components. 9) Solder in a well ventilated area. If a high concentration of freon is present, an open flame will create phosgene gas which can be harmful. ;;;; ;;;;;; PROPER SOLDERING Joint clearances should be maintained so that the brazing alloy will flow between the closely mated surfaces rather than forming large fillets. This films make the strongest joints, capillary attraction also work best with close ;; tolerance. The best clearance is between 0.01" to 0.03", the amount of lap will be ;;;; ;;;; approximately 3/8" depending on the sweging tool used. (Figure 1.) GOOD FIT POOR FIT PROPER JOINT FIT CLEARANCE .001"TO .003" Joint Clearance. Figure 1 CLEANING TUBING To make a sound, leak tight joint, the brazing alloy when raised to brazing temperature, must wet and flow freely over the entire surface of the tubing in the joint area. To assure this, the tubing surfaces must be free of all dirt, grease, oil and oxides otherwise the alloy will not wet and flow properly over any surface with these elements present. Cleaning can be done with an abrasive cloth or steel wool. Never blow into the tubing because this will introduce a lot of moisture into the system. Open tubing joints should be covered if exposed for long periods of time. EMERY CLOTH ;;;;;;KEEP TUBE IN ;;;;;;DOWNWARD POSITION Cleaning Tubing. Figure 2 PROPER FLUXING Flux is necessary when using silver solder; it is not required when using silfos on copper to copper joints. To do a good job the flux should cover the tube surface completely. Be careful not to introduce any flux inside the tubing. Fluxing should be done after the tubing is mated together and just before brazing is done. Do not allow it to dry out. When brazing, the flux should become entirely liquid and clear, like water. The temperature will be at 1100˚F and only a little more heat will allow the alloy to flow freely into the joint.3 3/8" SILVER ALLOY INNER CONE TORCH STEM Directing Torch Flame to Copper Tubing. Figure 3 10