Robinson also said the aluminum coils are superior in his coastal area of St. Petersburg, FL. "The effects of salty air on copper coils is not good. I can't say that about Spine Fin - and we have dealt with a number of different manufacturers over the years."

Robinson noted that manufacturers other than Trane often place restrictions on usage and the application of their equipment in coastal environments. "Normally they will make some disclaimer that they don't want their equipment installed within a half mile, two miles, etc.," he said. "They each have a different standard.

"Trane has no restrictions on the use of their units and their coils in the coastal environment and they warranty their equipment. That speaks of their experience with their coil and the overall quality of that coil's construction."

Without leaks, repairing Spine Fin coils is virtually unheard of. Should a coil leak, however, the manufacturer usually replaces it, said Robinson - "which is rather easy to replace due to the construction of the unit and the way they do it," he said.

FEWER JOINTS, FEWER LEAKS
Folks from Trane and American Standard's Residential Systems Group (Tyler, TX) discussed the finer points of their coil's design.

"Where coils are apt to leak is at joints; one of the points that leads to the use of Spine Fin is the fact it has far, far fewer joints
than does a plate fin coilk," explained Jim Crawford, former director of Technology, now director of Regulatory Affairs for Trane. "That doesn't make plate fin [coils] good or bad. That's just the intrinsic difference."

The manufacturer explained that its coil is manufactured on patented, high-speed machines that cut, form, and wrap aluminum ribbons around aluminum tubing. The tubing rises through a blue adhesive bath in the center of the machine; the bath coats the tube. Tension rollers wrap the fin ribbons tightly to the tube with the bonding adhesive to ensure good heat transfer. The extruded adhesive forms a barrier against capillary attraction, which might draw moisture into the crevice between the base of the fin and the tube. By sealing moisture and electrolytes out of the tube/fin space, galvanic and crevice corrosion is minimized, the company said.

Spine Fin coils are fabricated in continuous lengths. Brazed connections are required only at the coil (or circuit) inlet and outlet. This configuration helps eliminate end turns and reduces potential leaks, the company said.

According to the manufacturer, a typical 2.5-ton air conditioner or heat pump equipped with a plate fin coil requires approximately 30 brazed joint connections; a modern Trane or American Standard unit of the same size requires about 10.

"The issue was raised about the copper-to-aluminum connect1on in the coil," said Crawford, "and that brings you back to how good of a joint do you make? Do you know what you're doing? How many joints do you make? With Spine Fin coils, we make fewer joints. Therefore, there is less of a propensity to have a problem from that standpoint. The people who are doing this have a great deal of experience."