Is it possible to use R32 for the aluminum line set?

Generally speaking, a copper line set is a big amount of item used for split air conditioner installation. because Copper not only has a higher conductivity than aluminum, but is more ductile, with relatively high tensile strength, and can be soldered.

Although Aluminum is comparatively less conductive than 60% of copper, Aluminum has only 30 percent of the weight of copper. That means that a bare aluminum tube weighs half as much as a bare copper tube that has the same electrical resistance. Aluminum is generally more inexpensive when compared to copper conductors.

Regarding air conditioner assembly kits, we should focus on what’s the performance of R32 that applies to Aluminum line sets.

what condition R32 can be used for the aluminum line set?

R32 is short of dichloromethane, its molecular formula is ch2f2. it is a next-generation refrigerant that efficiently carries heat and has a lower environmental impact.

The advantage of R32.

many air conditioning manufacturers are adopting for its performance in regards to the environment, energy consumption, efficiency, and safety. 

The disadvantage of R32.

the refrigerant R32 is flammable and explosive, when the refrigerant leaks during the installation, maintenance, or use of the air conditioner, it is prone to explosion hazards, which will endanger personal safety.

Performance of R32 

The operating pressure of the R32 refrigerant air conditioner is similar to that of R410A, and the low pressure is about 0.8-1.0MPa. Low pressure is 0.5MPa or 5kg, high pressure is 1.8MPa or 18kg, balance pressure is 1MPa or 10kg.

So we’re sure R32 could operate running in an aluminum line set according to R32’s characteristic and literally depend on the aluminum type choice.

What kind of aluminum line sets are good used for R32?

According to R32’s characteristics like flammable and explosive, that is important to choose the right metal to make air conditioner assembly kits.

Aluminum alloy grade 

What aluminum grade to use for the aluminum line set? 1060 and 3003 alloy is the most widely used aluminum alloy. let us compare 1060 and 3003 alloy grades and find out which one is best for the R32 refrigerant.

1060 VS 3003 for aluminum line set

The type of aluminum grade you choose ultimately depends on how you intend to use the metal, 6 Things to Consider When Choosing an Aluminum Grade:

Aluminum purity: 1060 commercially pure aluminum more than 99.6%. It is soft and ductile, 3003 is also called pure aluminum more than 99.3% with added manganese.

Corrosion resistance: 3003 alloy aluminum has excellent corrosion resistance, and workability.1060 alloy is poor corrosion resistance, it is rapidly oxidized in air.

Formability or workability: 1060 and 3003 are both excellent formability and workability in mechanical properties, they are soft and ductile and have excellent workability, making them ideal for applications with difficult forming.

Weldability: 1060 and 3003 soft aluminum tubing have excellent weldability, but 3003 alloy is a little more difficult than 1060alloy in processing, the Weldability of the 3003 Aluminum is a challenge for process technology.

Strength: 3003 alloys with added manganese to increase its strength (20% stronger than the 1060 grade). 1060 alloy tensile strength 60 Mpa average, otherwise 3003 alloys can reach 120-140 Mpa.

Typical end-use applications: 3003 alloy grade is better performance in corrosion resistance and strength, for R32 refrigerant application, 3003 alloy is the better choice for R32 actually.

The leak is an important factor to judge weldability.

Dichloromethane is a raw material used in the production of R32, it is flammable and explosive that requires pipe strict tightness and pressure bearing.

The pressure and tightness test is the regular measurement to judge leaks.

Is the pipe wall thickness an important factor for pressure tests?

the answer is certainly, to get good pressure and tightness performance, for R32 we suggest pipe samples wall thickness for aluminum line set:

¼ aluminum pipe wall thickness: 0.8mm

⅜  aluminum pipe wall thickness: 0.8mm

½  aluminum pipe wall thickness: 1.0mm

⅝  aluminum pipe wall thickness: 1.1mm

¾  aluminum pipe wall thickness: 1.2mm

based on the above pipe wall thickness, we could conduct a pressure test and tightness test 

Pressure test 

3003 aluminum tubing pressure strength more than 4.5Mpa, it is fit for the operating pressure of the R32 refrigerant air conditioner (high pressure is 1.8MPa or 18kg)

Tightness test

Fulfilled 7.5 Mpa Nitrogen leak detection, after 48 hours, no leak happens requirement that shows pipe tightness is qualified.

How to judge a qualified aluminum line set for R32?

The performance of weldability is an important factor for aluminum line sets. as we know aluminum line set end should weld a part of copper tubing that connects flaring nuts with the service valve

what do you think of butt-welding for copper and aluminum?

copper &  aluminum butt welding is a common technology for welding copper and aluminum two different melting point metal materials.

Copper has a melting temperature of 1984°F; Aluminum has a melting temperature of 1221°F. While copper transfers heat faster than almost any other metal, copper doesn’t mount to other surfaces very well or very rigidly. So, copper is welded to aluminum, allowing the aluminum to be used as the mounting surface

The temperature of butt-welding

Electrical butt welding technical is matching welding temperature point 1058°F with Copper and aluminum connection strongly and solidly, coming out new material AL4CU9.

Welding parts condition

The welding parts point area must be more than 6mm, which could promise welding durability and stability, leak happens when copper leaves aluminum in application or installation actually.

The surface of welding parts must be smooth and fusing together without any bulges cracks, from this drawing we could find the difference between the two welding parts.

Leak Test

Make sure the parts are clean and dry before leak testing, two types of leak detection for aluminum line set, the easy way to put it in the water and see any bubble appear or not to judge the leak condition. another type is helium leak detector.

Where to buy the aluminum assembly kit for R32?

Changzhou Grana industry metal is a professional manufacturer of aluminum line set for over 20 years, they import electrical butt welding technical origin from Korea and get authorized patent No.10-1057068 

R32 is quickly becoming the refrigerant of choice for many AC manufacturers, the 3003 aluminum line set is the trend of air conditioner assembly kits.

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