Flaring is a tube-joining technique that creates a 45-degree conical sealing surface on copper tubing for use with compression fittings in refrigerant systems. The flared end slides into a matching fitting and is compressed by a nut, creating a metal-to-metal seal that withstands high pressures up to 600 PSI. Proper flaring is essential for leak-free refrigerant connections.
Flaring Process and Standards
Technicians use flaring tools with correct die sizes matching tubing outer diameter (1/4-inch, 3/8-inch, 1/2-inch, 5/8-inch, and 3/4-inch are common). The tubing is inserted into the die, and the flaring cone creates the 45-degree angle. Flare quality depends on proper tube cutting, deburring, and die alignment. Over-tightening the flare nut causes cracking; proper torque specifications must be followed (typically 10-15 foot-pounds for smaller sizes).
HVAC Applications and Reliability
Flared connections are standard for split-system air conditioners, heat pumps, and refrigeration equipment. Faulty flares create refrigerant leaks that reduce capacity and efficiency, requiring system repairs or replacement. EPA Section 608 certification requires proper knowledge of flaring techniques. Well-executed flares last the lifetime of equipment, typically 12-20 years, whereas poor flares fail within months of operation.