Soldering an air conditioning circuit

The meticulous design of the piping for an air conditioning system is a guarantee of its efficiency. The refrigeration technician then cuts his copper pipes. Finally, he welds the air conditioning pipes with a blowtorch.

The refrigeration technician’s tools.

The refrigeration technician’s tools are subject to conformity checks every year. You must equip yourself with a station and a recovery bottle, a manifold (also called manometer or by-pass) to diagnose and intervene on the refrigeration installation, a balance, a gas detector and a vacuum pump.

You will also need small tools: wrench, pliers, ratchet, screwdriver, etc.

The refrigeration technician’s tooling for air conditioning pipe welding.

For manipulating and welding air conditioning pipes, you must provide the following tools:

• flashlight ;
• bending machine ;
• pipe cutter ;
• deburrer ;
• Welding gas (argon is recommended);
• Vacuum gauge to measure the value of the residual gas pressure in a vacuum tube.

Preparation for air conditioning pipe welding

Piping Design

The refrigeration engineer’s first task is to design his or her air conditioning system and determine the circuit that the copper pipes must follow. Locate the lengths to be cut, as well as the elbows to be provided.

The cutting of copper pipes

The cutting of the copper pipes must be perfect. To this end, you must ban the use of the saw which could result in an uneven cut, with many burrs. Prefer the pipe cutter.

In any case, you must deburr the cut part of the tubes. Make sure to remove the internal burrs, directing the pipe downwards to avoid copper particles entering inside.

The welded joints.

All the parts that will be screwed together require the use of a dudgeon. Otherwise, the lengths are welded using a blowtorch. You have two solutions.

You practice classic welding.

You proceed by flaring: one of the tubes is beveled so that its inner diameter equals the outer diameter of the other tube, over at least ten centimeters. The two tubes are then fitted together.

The elbows

The changes in direction of the circuit imply that the pipes must be bent or the refrigeration technician must use elbows which will be welded.

The welding of air conditioning pipes

The flare joint consists of two parts, a male and a female. This copper/brass joint must be brazed with a blowtorch. To prevent the brass from melting too quickly, while the copper needs to be heated more, your rod must contain a minimum of 35% silver.

Prepare your flare connection by cleaning and degreasing both parts. Use sandpaper for the part that needs to be welded. Remove all the dust generated by the abrasion, before welding the air conditioning pipes. Use a few drops of refrigerant oil so that the assembly slides easily when you tighten the nut and the counter nut.

Argon gas is the most recommended for welding air conditioning systems, especially for connections using an elbow, reducer, or sleeve. The brazing being done directly from copper to copper, your rod may only contain 5% silver. Prepare the welding by degreasing the supports and passing them through abrasive paper.

Elbows can be made by brazing or bending a copper bar. When heating the copper, it is important to let it cool in the open air to avoid generating thermal shock which could be likely to break the molecules.