Silver soldering the copper lines to an air conditioner's condenser unit is not rocket science, but it does require attention to detail. The refrigerant flowing in the inlet line is under extremely high pressure, and the slightest imperfection in the soldered joint will allow the freon to escape into the environment. Silver soldering is not difficult, but it will take patience to get it right the first time. You can do it, and do it right if you follow these easy steps.
Things You'll Need
- MAPP Turbo-Torch, auto-lighting
- Sta-Bright Silver solder flux
- Silver solder rods
- Emery cloth
- Pipe cleaning brush
- Shop rags
Clean the outside of the high-pressure and low-pressure copper lines with the emery cloth. Starting at the end of the lines, remove all dirt and oxidation for 1 to 1-1/2 inches. A properly cleaned line will shine a bright copper color. You must work quickly because you need to complete the silver soldering process before any oxidation has a chance to take place.
Clean the insides of the swaged, enlarged ends of the inlet and outlet lines on the condenser. The high-pressure inlet line is larger in diameter than the low-pressure outlet line on the condenser unit.
Coat the outside of the copper lines coming from the compressor and the inside of the swaged nipples on the condenser unit with Sta-Brite silver solder flux. Apply the flux sparingly to the outside of the copper lines because you do not want excess flux entering the condenser unit. Push both copper lines into the matching swaged nipples until the copper lines bottom out against the shoulders of the swaged ends.
Open the valve on the Turbo-Torch and pull the trigger to light the torch. Adjust the valve until the inner, blue flame is between 1/2 and 3/4 of an inch long and slightly separated from the torch's nozzle.
Place the tip of the blue flame on the swaged line, moving it around the swaged end. When the line heats up to a cherry red, touch the silver solder rod to the point where the line meets the swaged end. The silver solder will melt and flow into and around the joint by capillary action generated by the heat. When the silver solder starts to drip freely from the joint, remove the solder and the torch. Wipe off the excess solder from the joint with a wet shop rag.