Identification Methods Before Purchase
Check official labels: Look for terms like "pure copper tubing" or "red copper" on the product details page, manual, or unit nameplate; avoid vague descriptions such as "copper-aluminum composite tubing" or "lightweight heat exchanger."
Compare unit weight: For models of the same capacity, an outdoor unit with all-copper tubing weighs 2–3 kg more than one with aluminum tubing; a 1.5-HP unit with pure copper tubing weighs approximately 25–30 kg, whereas aluminum-tubing models usually weigh less than 22 kg.
Visual Identification After Delivery
Check color under insulation: Gently peel back the insulation on the connecting pipe; copper tubing appears reddish-purple or rose-gold, while aluminum tubing is silvery-white. Copper-aluminum composite tubing will show distinct layering.
Scratch test:Lightly scratch the pipe surface with a small knife; copper tubing remains copper-colored, whereas aluminum tubing disguised with a copper coating will reveal a silvery-white aluminum inner layer.
Bend test: Copper tubing is hard and resilient, springing back without easily deforming; aluminum tubing is softer, deforming immediately upon bending without springing back, and is prone to developing micro-cracks at the bend.
Magnet test: Neither pure copper nor pure aluminum is magnetic; if a magnet sticks to the tubing, it indicates a nickel-plated iron pipe masquerading as copper-discard it immediately.