Aluminum evaporator coils

Q   A recent update by a manufacturer indicated that they will be going back to aluminum evaporator coils. How can this be justified to the public and to the service repair sector because of previous problems with aluminum?

A   Panelist 1 (Jack Bartell): More than likely, the manufacturer that you speak of is confident they can insure you don't have stress fractures and cracks on aluminum and brazing issues in the field for repair. Somehow, I guess they've managed to overcome that and, if so, more power to them.

As a former technician, I would probably be suspect of aluminum evaporator coils and not be one of the first to purchase. However, in this day and age, every manufacturer is charged with trying to meet not only the SEER requirements that we face, and, of course, in another year that will be 13 SEER.

We also try and stay ahead of the pack by developing units with SEER levels that meet the requirements of the more demanding customers. We also look at things with regard to cost.

If you can make an aluminum coil work effectively and somehow prove that you can realistically keep the warranties down, then that is something a manufacturer may try. We're always trying to do things to produce not only a better and a more efficient product, but one that, quite honestly, is more cost effective for those high-efficiency levels.

As SEER levels are forced higher and higher, there are so many things that manufacturers are looking at, such as a number of different evaporator and condenser designs. Car manufacturers looked at other forms in

the 1970s when they tried all-aluminum blocks and that didn't quite work out. But manufacturing processes change so I wouldn't rule anything out. In fact, there may be a workable solution.

Panelist 2 (Sherri Wilkerson, CM): At this time, Carrier, nor any of its subsidiaries, is looking at aluminum. However, I think some of the fear is coming from not just efficiency ratings but formicary corrosion, which has been a huge factor for most of the manufacturers.

I wouldn't be surprised if some manufacturers don't look again in that direction. Whether it's good or bad, we have to trust that the testing will be there.

Question by John Rybicki, Abbot Service, Marrietta , Ga. Answers by Jack Bartell, manager of training services, York Unitary Products Group, and Sherri Wilkerson, CM, senior product support engineer, Carrier Corp.