What Is a Copper Pancake Coil?
A copper pancake coil is a continuous length of small-diameter copper tube, fully annealed and level-wound into a flat spiral coil. The name comes from the flattened, disc-like shape of the coil. Pancake coils are the standard packaging form for air-conditioning and refrigeration (ACR) tubing, because a single coil can carry tens of meters of tube with no brazed joints, which is the most reliable way to run a refrigerant line.
Material and Standards
Pancake coils are normally made from phosphorus-deoxidized copper, most commonly DHP copper (C12200) and occasionally DLP (C12000), supplied to ASTM B280 for ACR service, ASTM B75 for general seamless tube, or ASTM B743 for coiled tube. The tube is fully annealed to a soft temper so it can be straightened and bent by hand or with simple tools during installation. Common outside diameters are 6.35 mm (1/4 in), 9.52 mm (3/8 in), 12.7 mm (1/2 in), 15.88 mm (5/8 in), and 19.05 mm (3/4 in), with wall thicknesses per the applicable standard.
Types of Copper Pancake Coils
Bare tube coils: plain soft-drawn copper tube, the most common type for field-installed ACR lines.
Pre-insulated coils: tube wrapped in closed-cell foam insulation for chilled-water and refrigerant lines where condensation control is required.
Coils with factory fittings: one or both ends flared, capped, or fitted with connections to speed installation.
Refrigeration-grade coils: internally cleaned, dehydrated, and sealed with a nitrogen or inert-gas charge to prevent contamination.
Finned-tube coils: finned heat transfer coils assembled into units, supplied as components rather than loose tube.
Key Features
| Feature | Why It Matters |
|---|---|
| Continuous length | No joints in the line, fewer leak points |
| Soft annealed temper | Bends easily by hand; low springback |
| Clean, dehydrated bore | Dry and particle-free for refrigerant circuits |
| Flat winding | Stable stacking, compact transport and storage |
| High thermal conductivity | Efficient heat transfer in evaporator and condenser lines |
Advantages Over Straight Lengths
Fewer brazed joints mean fewer potential leak points and lower installation labor.
Long continuous runs can be pulled through walls and trays without couplings.
Less scrap: the installer cuts only the length actually needed.
Lower freight cost per meter because the coil packs densely.
Applications
Pancake coils are used in split air conditioners, heat pumps, refrigeration cabinets, chillers, solar water heaters, underfloor heating manifolds, and water supply connections. In each case the soft tube is straightened, cut, flared, and connected with mechanical fittings or brazed joints, then pressure-tested to confirm leak tightness.
Frequently Asked Questions
Q: What is the difference between a pancake coil and a drum coil?
A: A pancake coil is a small flat disc typically holding 5 to 30 meters of tube; a drum or spool coil is a larger cylindrical package for long runs, usually machine-level-wound.
Q: Can a pancake coil be reused after bending?
A: Yes, provided the tube is not kinked, work-hardened beyond the required ductility, or damaged during straightening. Re-annealing restores soft temper if needed.
Q: What copper grade is used for ACR pancake coils?
A: Phosphorus-deoxidized copper, typically C12200 (DHP) or C12000 (DLP), per ASTM B280 for refrigeration service.
Q: How long is a typical pancake coil?
A>Common lengths are 15, 20, 25, and 30 meters, depending on diameter and the regional packaging standard.
Q: Is pancake coil tube suitable for drinking water?
A: Yes, if it is supplied to a water-tube standard such as ASTM B88 with the required internal cleanliness; a dedicated potable-water grade should be specified.
Q: Why must ACR coil be dehydrated and sealed?
A>Moisture and particles cause ice blockages, acid formation, and compressor damage in refrigeration circuits. Factory sealing keeps the bore clean until installation.
