The Ultimate Guide to Choosing the Perfect Insulated Pair Coil for Your Air Conditioner

The Ultimate Guide to Choosing the Perfect Insulated Pair Coil for Your Air Conditioner

The choice of pair coil is crucial when installing or maintaining an air conditioner. Defective installation can lead to water leakage, electrical shock, or even fire hazards. In this guide, we'll walk you through the essential steps to ensure you pick the perfect Insulated Pair Coil for your air conditioner.

It's essential to emphasize at first that installing an air conditioner in Australia is not a DIY endeavor. It is illegal to undertake such installations without the appropriate licensing and qualifications. Always enlist the services of a licensed electrician to install and maintain your air conditioning system, ensuring compliance with regulations and safety standards.

Step 1: Consult the Brand Brochure of Your Air Conditioner

When selecting a pair coil for your air conditioner, it's essential to start with the basics. Begin by confirming the model of your unit, this will help you find the specific requirements.

Consulting brochures from the most air conditioner brands reveals that the advised type of refrigerant and the liquid and gas sides are typically found in the brand brochure which you can find from the brand official website, not the user manual. Search for terms like "piping" or "pipe size" in the brochure and match them with your model number to get the correct specifications.

To help you, we've attached pictures from brochures of three major brands, Midea, Mitsubishi and Fujitsu. These examples show where to find the necessary information and how to interpret it correctly. 

Please note: In some brochures, the unit of length is shown in millimeters rather than inches. Please refer to the converter chart below to convert millimeters to inches.

There are 5 common sizes of copper pipes. See table:

Ø Diameter (in inches)  Ø Diameter (in mm)
1/4'' 6.35  mm
3/8'' 9.52  mm
1/2'' 12.70 mm
5/8'' 12.88 mm

19.05 mm


You can also refer to the pipe size chart below, which summarizes the main brands along with their suitable pipe sizes.

Air Conditioner Pair Coil/Copper Pipe Sizing Chart for Split System

Understanding these details will lay the groundwork for your pipe selection process.

Step 2: Opt for Copper Pipes Containing 99.9% Pure Copper

Did you know that non-pure copper pipe, such as those mixed with aluminium or other materials can lead to several potential issues in an air conditioning system?

When installing an air conditioner, using pure copper pipes is essential for ensuring durability and efficiency. According to the Copper Development Association Inc., all tubes supplied to ASTM standards* (ASTM International develops and publishes approximately 12,000 technical standards used worldwide, ensuring the quality and reliability of materials) are a minimum of 99.9% pure copper. The copper used for these tubes, deoxidized with phosphorus, is known as UNS C12200 or DHP1 Copper. Any copper tube containing less than 99.9% pure copper is not permitted for use in the HVAC industry.

Using non-pure copper pipes in air conditioning installations can lead to several issues, including corrosion, reduced thermal conductivity, compatibility problems, decreased mechanical strength, and a shorter system lifespan. 

At this juncture, it's worth introducing our premium copper pipes. Made with 99.96% pure copper and free from mixed aluminum, our pipes are meticulously crafted from top-grade copper, guaranteeing superior performance and peace of mind for homeowners and HVAC electricians. Choose our premium copper pipes to ensure the longevity and efficiency of your air conditioning system.

Step 3: Ensure Compliance with AS/NZS 1571

Tips: Pair coils comply with the AS/NZS 1571 standard will be marked 'AS/NZS 1571' on the outer packaging and the pipe insulation.

When selecting copper pipes for air conditioning installations, ensuring compatibility with Australian standards is crucial. According to the newsletter from Australia Government the Department of Environment and Energy in 2019, if your air conditioner uses refrigerants such as R32 or R410A, compliance with AS/NZS 1571 is especially critical, which specifies the requirements for copper seamless tubes used in air conditioning and refrigeration systems. These refrigerants demand greater wall thickness to withstand the elevated pressures, making adherence to standards a non-negotiable aspect of pipe selection.

AS/NZS 1571 was approved on behalf of the Council of Standards Australia on 25 September 1995 and on behalf of the Council of Standards New Zealand on 11 September 1995. 

This standard specifies requirements for round, seamless copper tubes manufactured from phosphorus-deoxidized copper containing high residual phosphorus (UNS alloy C12200) intended for use in air-conditioning and refrigeration.

For the designation, tubes shall be supplied in straight lengths or coils. Tubes in coil form shall be supplied in the O temper which means the tube need to be in a fully softened condition (annealed).

Thus, the primary criterion for determining if a pipe is suitable for your refrigerant lies in verifying its adherence to the Australian standard number 1571.

To summarize, by following the steps outlined in this guide, you can ensure optimal performance, efficiency, and safety for your air conditioning system. Begin by sorting out the pipe size according to the brand brochure, then choose a high-grade copper pipe (minimum containing 99.9% copper) that complies with AS/NZS 1571.

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